CVE-2024-44946· NVD / CVE Program· CNA Linux

kcm: Serialise kcm_sendmsg() for the same socket.

Noroxi assessment

Priority: Monitor (action score 22/100)

Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
Probability of exploitation in the next 30 days: 0.86% (FIRST EPSS); higher than 58% of all records.
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 00425508f30baa5ab6449a1f478480ca7cffa6da, 6633b17840bf828921254d788ccd15602843fe9b, 72da240aafb142630cf16adc803ccdacb3780849; Azure Linux 3.0 ARM 6.6.51.1-1; Azure Linux 3.0 x64 6.6.51.1-1.
Severity is disputed: the assigning authority (CNA) scores it 7.8, NVD 5.5.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 00425508f30baa5ab6449a1f478480ca7cffa6da, 6633b17840bf828921254d788ccd15602843fe9b, 72da240aafb142630cf16adc803ccdacb3780849; Azure Linux 3.0 ARM 6.6.51.1-1; Azure Linux 3.0 x64 6.6.51.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: kcm: Serialise kcm_sendmsg() for the same socket. syzkaller reported UAF in kcm_release(). [0] The scenario is 1. Thread A builds a skb with MSG_MORE and sets kcm->seq_skb. 2. Thread A resumes building skb from kcm->seq_skb but is blocked by sk_stream_wait_memory() 3. Thread B calls sendmsg() concurrently, finishes building kcm->seq_skb and puts the skb to the write queue 4. Thread A faces an error and finally frees skb that is already in the write queue 5. kcm_release() does double-free the skb in the write queue When a thread is building a MSG_MORE skb, another thread must not touch it. Let's add a per-sk mutex and serialise kcm_sendmsg(). [0]: BUG: KASAN: slab-use-after-free in __skb_unlink include/linux/skbuff.h:2366 [inline] BUG: KASAN: slab-use-after-free in __skb_dequeue include/linux/skbuff.h:2385 [inline] BUG: KASAN: slab-use-after-free in __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline] BUG: KASAN: slab-use-after-free in __skb_queue_purge include/linux/skbuff.h:3181 [inline] BUG: KASAN: slab-use-after-free in kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691 Read of size 8 at addr ffff0000ced0fc80 by task syz-executor329/6167 CPU: 1 PID: 6167 Comm: syz-executor329 Tainted: G B 6.8.0-rc5-syzkaller-g9abbc24128bc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0x178/0x518 mm/kasan/report.c:488 kasan_report+0xd8/0x138 mm/kasan/report.c:601 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381 __skb_unlink include/linux/skbuff.h:2366 [inline] __skb_dequeue include/linux/skbuff.h:2385 [inline] __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline] __skb_queue_purge include/linux/skbuff.h:3181 [inline] kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691 __sock_release net/socket.c:659 [inline] sock_close+0xa4/0x1e8 net/socket.c:1421 __fput+0x30c/0x738 fs/file_table.c:376 ____fput+0x20/0x30 fs/file_table.c:404 task_work_run+0x230/0x2e0 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x618/0x1f64 kernel/exit.c:871 do_group_exit+0x194/0x22c kernel/exit.c:1020 get_signal+0x1500/0x15ec kernel/signal.c:2893 do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249 do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline] el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Allocated by task 6166: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x70/0x84 mm/kasan/generic.c:626 unpoison_slab_object mm/kasan/common.c:314 [inline] __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3813 [inline] slab_alloc_node mm/slub.c:3860 [inline] kmem_cache_alloc_node+0x204/0x4c0 mm/slub.c:3903 __alloc_skb+0x19c/0x3d8 net/core/skbuff.c:641 alloc_skb include/linux/skbuff.h:1296 [inline] kcm_sendmsg+0x1d3c/0x2124 net/kcm/kcmsock.c:783 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_sendmsg+0x220/0x2c0 net/socket.c:768 splice_to_socket+0x7cc/0xd58 fs/splice.c:889 do_splice_from fs/splice.c:941 [inline] direct_splice_actor+0xec/0x1d8 fs/splice.c:1164 splice_direct_to_actor+0x438/0xa0c fs/splice.c:1108 do_splice_direct_actor ---truncated---

MediumCVSS 5.5 · v3.1—Proof of concept Fix available

Published: Aug 31, 2024
Updated: Aug 5, 2026
EPSS: 0.8% · 58th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 22 / 40 · 5.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.8%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 5.5
CNA · Linux: 7.8; 2.3 point gap

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
Proof of concept exists, no weaponized module
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

ProductVersion

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel4.6 and later · before 6.1.107
linux linux kernel6.2 and later · before 6.6.48
linux linux kernel6.7 and later · before 6.10.7
linux linux kernel6.11

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 4.6affected
- ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 8c9cdbf600143bd6835c8b8351e5ac956da79aecaffected · git
- ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 6633b17840bf828921254d788ccd15602843fe9baffected · git
- ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before eb06c8d3022ce6738711191c89f9b3e9cfb91914affected · git
- ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before fa6c23fe6dcac8c8bd63920ee8681292a2bd544eaffected · git
- ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 72da240aafb142630cf16adc803ccdacb3780849affected · git
- ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 00425508f30baa5ab6449a1f478480ca7cffa6daaffected · git
- ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 9c8d544ed619f704e2b70e63e08ab75630c2ea23affected · git
- ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 807067bf014d4a3ae2cc55bd3de16f22a01eb580affected · git
- before 4.6not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.112-1	6.1.112-1
Debian:13	linux	before 6.10.7-1	6.10.7-1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-default-base	before 5.3.18-150200.24.206.1.150200.9.107.1	5.3.18-150200.24.206.1.150200.9.107.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-docs	before 5.3.18-150200.24.206.1	5.3.18-150200.24.206.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-obs-build	before 5.3.18-150200.24.206.1	5.3.18-150200.24.206.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-preempt	before 5.3.18-150200.24.206.1	5.3.18-150200.24.206.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-source	before 5.3.18-150200.24.206.1	5.3.18-150200.24.206.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-syms	before 5.3.18-150200.24.206.1	5.3.18-150200.24.206.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-64kb	before 5.3.18-150300.59.179.1	5.3.18-150300.59.179.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-default-base	before 5.3.18-150300.59.179.1.150300.18.105.2	5.3.18-150300.59.179.1.150300.18.105.2
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-docs	before 5.3.18-150300.59.179.1	5.3.18-150300.59.179.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-obs-build	before 5.3.18-150300.59.179.1	5.3.18-150300.59.179.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-preempt	before 5.3.18-150300.59.179.1	5.3.18-150300.59.179.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-source	before 5.3.18-150300.59.179.1	5.3.18-150300.59.179.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-syms	before 5.3.18-150300.59.179.1	5.3.18-150300.59.179.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-64kb	before 5.14.21-150400.24.136.1	5.14.21-150400.24.136.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-docs	before 5.14.21-150400.24.136.1	5.14.21-150400.24.136.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-obs-build	before 5.14.21-150400.24.136.1	5.14.21-150400.24.136.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-source	before 5.14.21-150400.24.136.1	5.14.21-150400.24.136.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-syms	before 5.14.21-150400.24.136.1	5.14.21-150400.24.136.1
SUSE:Linux Enterprise Live Patching 15 SP2	kernel-default	before 5.3.18-150200.24.206.1	5.3.18-150200.24.206.1
SUSE:Linux Enterprise Live Patching 15 SP2	kernel-livepatch-SLE15-SP2_Update_53	before 1-150200.5.3.1	1-150200.5.3.1
SUSE:Linux Enterprise Live Patching 15 SP3	kernel-default	before 5.3.18-150300.59.179.1	5.3.18-150300.59.179.1
SUSE:Linux Enterprise Live Patching 15 SP3	kernel-livepatch-SLE15-SP3_Update_49	before 1-150300.7.3.2	1-150300.7.3.2

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
89Now
CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
85Now
CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
83Now

Published before and after this one in the same product

← EarlierCVE-2024-44944Aug 30, 2024 · netfilter: ctnetlink: use helper function to calculate expect ID
22Monitor
← EarlierCVE-2024-44945Aug 31, 2024 · netfilter: nfnetlink: Initialise extack before use in ACKs
31Monitor
Later →CVE-2024-44947Sep 2, 2024 · fuse: Initialize beyond-EOF page contents before setting uptodate
22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	00425508f30baa5ab6449a1f478480ca7cffa6da	Vendor (CNA)
Linux Linux	6633b17840bf828921254d788ccd15602843fe9b	Vendor (CNA)
Linux Linux	72da240aafb142630cf16adc803ccdacb3780849	Vendor (CNA)
Linux Linux	807067bf014d4a3ae2cc55bd3de16f22a01eb580	Vendor (CNA)
Linux Linux	8c9cdbf600143bd6835c8b8351e5ac956da79aec	Vendor (CNA)
Linux Linux	9c8d544ed619f704e2b70e63e08ab75630c2ea23	Vendor (CNA)
Linux Linux	eb06c8d3022ce6738711191c89f9b3e9cfb91914	Vendor (CNA)
Linux Linux	fa6c23fe6dcac8c8bd63920ee8681292a2bd544e	Vendor (CNA)
Azure Linux 3.0 ARM	6.6.51.1-1 · kernel	Microsoft (MSRC)
Azure Linux 3.0 x64	6.6.51.1-1 · kernel	Microsoft (MSRC)
CBL Mariner 2.0 ARM	5.15.167.1-1 · kernel	Microsoft (MSRC)
CBL Mariner 2.0 x64	5.15.167.1-1 · kernel	Microsoft (MSRC)
debian:linux	6.1.112-1 · Debian:12	Package registry (OSV)
suse:kernel-64kb	5.14.21-150400.24.136.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-default	5.14.21-150400.24.136.1 · SUSE:Linux Enterprise Micro 5.3	Package registry (OSV)
suse:kernel-default-base	5.14.21-150400.24.136.1.150400.24.66.1 · SUSE:Linux Enterprise Micro 5.3	Package registry (OSV)
suse:kernel-docs	5.14.21-150400.24.136.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-livepatch-SLE15-SP2_Update_53	1-150200.5.3.1 · SUSE:Linux Enterprise Live Patching 15 SP2	Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_32	1-150400.9.3.1 · SUSE:Linux Enterprise Live Patching 15 SP4	Package registry (OSV)
suse:kernel-obs-build	5.14.21-150400.24.136.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-rt	5.14.21-150400.15.97.1 · SUSE:Linux Enterprise Micro 5.3	Package registry (OSV)
suse:kernel-source	5.14.21-150400.24.136.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-source-rt	5.14.21-150400.15.97.1 · SUSE:Linux Enterprise Micro 5.3	Package registry (OSV)
suse:kernel-syms	5.14.21-150400.24.136.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	Package registry (OSV)
suse:kernel-zfcpdump	5.14.21-150400.24.136.1 · SUSE:Linux Enterprise Server 15 SP4-LTSS	Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Proof-of-concept repository on GitHub	stars:1	2024-09-01

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedAug 31, 2024
First PoCSep 1, 2024+1 d
TodayOct 24, 2026+784 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-24-1373 · Sep 2, 2024(Linux Kernel Güvenlik Bildirimi)

All national notices →

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

For records you follow, these changes also arrive as notifications. →

References

git.kernel.org/stable/c/00425508f30baa5ab6449a1f478480ca7cffa6da

Show all references (9 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records

Noroxi analysis

What does it mean in your environment?

We use this product, ask for help

Data sources and verification

CNA: Linux

CVE.org (CNA)Aug 5, 2026, 11:37 AM UTC
CISA ADPAug 5, 2026, 11:37 AM UTC
NVDAug 5, 2026, 11:37 AM UTC
FIRST EPSSOct 22, 2026, 12:00 AM UTC
OSV / GHSAOct 23, 2026, 3:18 AM UTC
MSRCOct 5, 2026, 3:24 AM UTC
PoC-in-GitHubOct 23, 2026, 3:18 AM UTC

Each line is when that source was last processed for this record.