NVD / CVE Program· CNA Linux

CVE-2026-23273: macvlan: observe an RCU grace period in macvlan_common_newlink() error path

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
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 19c7d8ac51988d053709c1e85bd8482076af845d, 1e58ae87ad1e6e24368dea9aec9048c758cd0e2b, 3d94323c80d7fc4da5f10f9bb06a45d39d5d3cc4.

Low priority for now. Upgrade to Linux Linux 19c7d8ac51988d053709c1e85bd8482076af845d, 1e58ae87ad1e6e24368dea9aec9048c758cd0e2b, 3d94323c80d7fc4da5f10f9bb06a45d39d5d3cc4 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: macvlan: observe an RCU grace period in macvlan_common_newlink() error path valis reported that a race condition still happens after my prior patch. macvlan_common_newlink() might have made @dev visible before detecting an error, and its caller will directly call free_netdev(dev). We must respect an RCU period, either in macvlan or the core networking stack. After adding a temporary mdelay(1000) in macvlan_forward_source_one() to open the race window, valis repro was: ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source (ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 &) ; sleep 0.5 ; ping -c1 -I p1 1.2.3.4 PING 1.2.3.4 (1.2.3.4): 56 data bytes RTNETLINK answers: Invalid argument BUG: KASAN: slab-use-after-free in macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) Read of size 8 at addr ffff888016bb89c0 by task e/175 CPU: 1 UID: 1000 PID: 175 Comm: e Not tainted 6.19.0-rc8+ #33 NONE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: <IRQ> dump_stack_lvl (lib/dump_stack.c:123) print_report (mm/kasan/report.c:379 mm/kasan/report.c:482) ? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) kasan_report (mm/kasan/report.c:597) ? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) ? tasklet_init (kernel/softirq.c:983) macvlan_handle_frame (drivers/net/macvlan.c:501) Allocated by task 169: kasan_save_stack (mm/kasan/common.c:58) kasan_save_track (./arch/x86/include/asm/current.h:25 mm/kasan/common.c:70 mm/kasan/common.c:79) __kasan_kmalloc (mm/kasan/common.c:419) __kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5657 mm/slub.c:7140) alloc_netdev_mqs (net/core/dev.c:12012) rtnl_create_link (net/core/rtnetlink.c:3648) rtnl_newlink (net/core/rtnetlink.c:3830 net/core/rtnetlink.c:3957 net/core/rtnetlink.c:4072) rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131) Freed by task 169: kasan_save_stack (mm/kasan/common.c:58) kasan_save_track (./arch/x86/include/asm/current.h:25 mm/kasan/common.c:70 mm/kasan/common.c:79) kasan_save_free_info (mm/kasan/generic.c:587) __kasan_slab_free (mm/kasan/common.c:287) kfree (mm/slub.c:6674 mm/slub.c:6882) rtnl_newlink (net/core/rtnetlink.c:3845 net/core/rtnetlink.c:3957 net/core/rtnetlink.c:4072) rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)

HighCVSS 7.8 · v3.1—No exploit Fix available

Published: Mar 20, 2026
Updated: Oct 19, 2026
EPSS: 0.1% · 2th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Linux: 7.8; NVD has not scored this yet; the score shown is the CNA’s.

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
No public exploit code on record
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.

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 kernel5.10.250 and later · before 5.10.252
linux linux kernel5.15.200 and later · before 5.15.202
linux linux kernel6.1.163 and later · before 6.1.165
linux linux kernel6.6.124 and later · before 6.6.128
linux linux kernel6.12.70 and later · before 6.12.75
linux linux kernel6.18.10 and later · before 6.18.14
linux linux kernel6.19.1 and later · before 6.19.4

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
- 6.19affected
- da5c6b8ae47e414be47e5e04def15b25d5c962dc and later · before 91e4ff8d966978901630fc29582c1a76d3c6e46caffected · git
- 5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a and later · before 3d94323c80d7fc4da5f10f9bb06a45d39d5d3cc4affected · git
- c43d0e787cbba569ec9d11579ed370b50fab6c9c and later · before 721eb342d9ba19bad5c4815ea3921465158b7362affected · git
- 11ba9f0dc865136174cb98834280fb21bbc950c7 and later · before 19c7d8ac51988d053709c1e85bd8482076af845daffected · git
- 986967a162142710076782d5b93daab93a892980 and later · before a1f686d273d129b45712d95f4095843b864466bdaffected · git
- cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66 and later · before d34f7a8aa9a25b7e64e0e46e444697c0f702374daffected · git
- f8db6475a83649689c087a8f52486fcc53e627e9 and later · before 1e58ae87ad1e6e24368dea9aec9048c758cd0e2baffected · git
- f8db6475a83649689c087a8f52486fcc53e627e9 and later · before e3f000f0dee1bfab52e2e61ca6a3835d9e187e35affected · git
- 5.10.250 and later · before 5.10.252affected · 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 6.1.170-1	6.1.170-1
Debian:13	linux	before 6.12.85-1	6.12.85-1
Debian:14	linux	before 6.18.14-1	6.18.14-1
SUSE:Linux Enterprise Live Patching 15 SP6	kernel-default	before 6.4.0-150600.23.112.1	6.4.0-150600.23.112.1
SUSE:Linux Enterprise Live Patching 15 SP6	kernel-livepatch-SLE15-SP6_Update_26	before 1-150600.13.3.1	1-150600.13.3.1
SUSE:Linux Enterprise Server 15 SP6-LTSS	kernel-64kb	before 6.4.0-150600.23.112.1	6.4.0-150600.23.112.1
SUSE:Linux Enterprise Server 15 SP6-LTSS	kernel-default-base	before 6.4.0-150600.23.112.1.150600.12.52.1	6.4.0-150600.23.112.1.150600.12.52.1
SUSE:Linux Enterprise Server 15 SP6-LTSS	kernel-docs	before 6.4.0-150600.23.112.1	6.4.0-150600.23.112.1
SUSE:Linux Enterprise Server 15 SP6-LTSS	kernel-obs-build	before 6.4.0-150600.23.112.1	6.4.0-150600.23.112.1
SUSE:Linux Enterprise Server 15 SP6-LTSS	kernel-source	before 6.4.0-150600.23.112.1	6.4.0-150600.23.112.1
SUSE:Linux Enterprise Server 15 SP6-LTSS	kernel-syms	before 6.4.0-150600.23.112.1	6.4.0-150600.23.112.1
SUSE:Linux Enterprise Server 15 SP6-LTSS	kernel-zfcpdump	before 6.4.0-150600.23.112.1	6.4.0-150600.23.112.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
90Now
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

Published before and after this one in the same product

← EarlierCVE-2026-23271Mar 20, 2026 · perf: Fix __perf_event_overflow() vs perf_remove_from_context() race
31Monitor
← EarlierCVE-2026-23272Mar 20, 2026 · netfilter: nf_tables: unconditionally bump set->nelems before insertion
31Monitor
Later →CVE-2026-23274Mar 20, 2026 · netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels
31Monitor

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	19c7d8ac51988d053709c1e85bd8482076af845d	Vendor (CNA)
Linux Linux	1e58ae87ad1e6e24368dea9aec9048c758cd0e2b	Vendor (CNA)
Linux Linux	3d94323c80d7fc4da5f10f9bb06a45d39d5d3cc4	Vendor (CNA)
Linux Linux	5.10.252	Vendor (CNA)
Linux Linux	5.15.202	Vendor (CNA)
Linux Linux	6.1.165	Vendor (CNA)
Linux Linux	6.12.75	Vendor (CNA)
Linux Linux	6.18.14	Vendor (CNA)
Linux Linux	6.6.128	Vendor (CNA)
Linux Linux	721eb342d9ba19bad5c4815ea3921465158b7362	Vendor (CNA)
Linux Linux	91e4ff8d966978901630fc29582c1a76d3c6e46c	Vendor (CNA)
Linux Linux	a1f686d273d129b45712d95f4095843b864466bd	Vendor (CNA)
Linux Linux	d34f7a8aa9a25b7e64e0e46e444697c0f702374d	Vendor (CNA)
Linux Linux	e3f000f0dee1bfab52e2e61ca6a3835d9e187e35	Vendor (CNA)
debian:linux	6.1.170-1 · Debian:12	Package registry (OSV)
suse:kernel-64kb	6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS	Package registry (OSV)
suse:kernel-default	6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Live Patching 15 SP6	Package registry (OSV)
suse:kernel-default-base	6.4.0-150600.23.112.1.150600.12.52.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS	Package registry (OSV)
suse:kernel-docs	6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS	Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6_Update_26	1-150600.13.3.1 · SUSE:Linux Enterprise Live Patching 15 SP6	Package registry (OSV)
suse:kernel-obs-build	6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS	Package registry (OSV)
suse:kernel-source	6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS	Package registry (OSV)
suse:kernel-syms	6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS	Package registry (OSV)
suse:kernel-zfcpdump	6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

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.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

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).

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: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
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:H/I:H/A:H

nvd-secondary

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

SSVC exploitation— → noneOct 16, 2026, 5:07 PM UTC
Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

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

References

git.kernel.org/stable/c/19c7d8ac51988d053709c1e85bd8482076af845d

Show all references (11 more)

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

All records