NVD / CVE Program· CNA Linux

CVE-2021-47598: sch_cake: do not call cake_destroy() from cake_init()

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: 0.25% (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 0d80462fbdcafd536dcad7569e65d3d14a7e9f2f, 20ad1ef02f9ad5e1dda9eeb113e4c158b4806986, 4e388232e630ebe4f94b4a0715ec98c0e2b314a3.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0d80462fbdcafd536dcad7569e65d3d14a7e9f2f, 20ad1ef02f9ad5e1dda9eeb113e4c158b4806986, 4e388232e630ebe4f94b4a0715ec98c0e2b314a3 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: sch_cake: do not call cake_destroy() from cake_init() qdiscs are not supposed to call their own destroy() method from init(), because core stack already does that. syzbot was able to trigger use after free: DEBUG_LOCKS_WARN_ON(lock->magic != lock) WARNING: CPU: 0 PID: 21902 at kernel/locking/mutex.c:586 __mutex_lock_common kernel/locking/mutex.c:586 [inline] WARNING: CPU: 0 PID: 21902 at kernel/locking/mutex.c:586 __mutex_lock+0x9ec/0x12f0 kernel/locking/mutex.c:740 Modules linked in: CPU: 0 PID: 21902 Comm: syz-executor189 Not tainted 5.16.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:586 [inline] RIP: 0010:__mutex_lock+0x9ec/0x12f0 kernel/locking/mutex.c:740 Code: 08 84 d2 0f 85 19 08 00 00 8b 05 97 38 4b 04 85 c0 0f 85 27 f7 ff ff 48 c7 c6 20 00 ac 89 48 c7 c7 a0 fe ab 89 e8 bf 76 ba ff <0f> 0b e9 0d f7 ff ff 48 8b 44 24 40 48 8d b8 c8 08 00 00 48 89 f8 RSP: 0018:ffffc9000627f290 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88802315d700 RSI: ffffffff815f1db8 RDI: fffff52000c4fe44 RBP: ffff88818f28e000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815ebb5e R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: ffffc9000627f458 R15: 0000000093c30000 FS: 0000555556abc400(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fda689c3303 CR3: 000000001cfbb000 CR4: 0000000000350ef0 Call Trace: <TASK> tcf_chain0_head_change_cb_del+0x2e/0x3d0 net/sched/cls_api.c:810 tcf_block_put_ext net/sched/cls_api.c:1381 [inline] tcf_block_put_ext net/sched/cls_api.c:1376 [inline] tcf_block_put+0xbc/0x130 net/sched/cls_api.c:1394 cake_destroy+0x3f/0x80 net/sched/sch_cake.c:2695 qdisc_create.constprop.0+0x9da/0x10f0 net/sched/sch_api.c:1293 tc_modify_qdisc+0x4c5/0x1980 net/sched/sch_api.c:1660 rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5571 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2496 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x904/0xdf0 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f1bb06badb9 Code: Unable to access opcode bytes at RIP 0x7f1bb06bad8f. RSP: 002b:00007fff3012a658 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f1bb06badb9 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000246 R12: 00007fff3012a688 R13: 00007fff3012a6a0 R14: 00007fff3012a6e0 R15: 00000000000013c2 </TASK>

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

Published: Jun 19, 2024
Updated: Aug 5, 2026
EPSS: 0.2% · 17th 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 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 7.8
CNA · Linux: 7.8; agree

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 kernel4.19 and later · before 4.19.222
linux linux kernel4.20 and later · before 5.4.168
linux linux kernel5.5 and later · before 5.10.88
linux linux kernel5.11 and later · before 5.15.11

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
- 4.19affected
- 046f6fd5daefac7f5abdafb436b30f63bc7c602b and later · before 4e388232e630ebe4f94b4a0715ec98c0e2b314a3affected · git
- 046f6fd5daefac7f5abdafb436b30f63bc7c602b and later · before 0d80462fbdcafd536dcad7569e65d3d14a7e9f2faffected · git
- 046f6fd5daefac7f5abdafb436b30f63bc7c602b and later · before 20ad1ef02f9ad5e1dda9eeb113e4c158b4806986affected · git
- 046f6fd5daefac7f5abdafb436b30f63bc7c602b and later · before f6deae2e2d83bd267e1986f5d71d8c458e18fd99affected · git
- 046f6fd5daefac7f5abdafb436b30f63bc7c602b and later · before ab443c53916730862cec202078d36fd4008bea79affected · git
- before 4.19not affected · semver
- 4.19.222 and later · up to and including 4.19.*not affected · semver
- 5.4.168 and later · up to and including 5.4.*not affected · semver
- 5.10.88 and later · up to and including 5.10.*not 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 5.15.15-1	5.15.15-1
openSUSE:Leap 15.5	kernel-azure	before 5.14.21-150500.33.63.1	5.14.21-150500.33.63.1
openSUSE:Leap 15.5	kernel-rt_debug	before 5.14.21-150500.13.64.1	5.14.21-150500.13.64.1
openSUSE:Leap 15.5	kernel-source-azure	before 5.14.21-150500.33.63.1	5.14.21-150500.33.63.1
openSUSE:Leap 15.5	kernel-source-rt	before 5.14.21-150500.13.64.1	5.14.21-150500.13.64.1
openSUSE:Leap 15.5	kernel-syms-azure	before 5.14.21-150500.33.63.1	5.14.21-150500.33.63.1
openSUSE:Leap 15.5	kernel-syms-rt	before 5.14.21-150500.13.64.1	5.14.21-150500.13.64.1
openSUSE:Leap Micro 5.5	kernel-rt	before 5.14.21-150500.13.64.1	5.14.21-150500.13.64.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-default-base	before 5.3.18-150200.24.200.1.150200.9.103.1	5.3.18-150200.24.200.1.150200.9.103.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-docs	before 5.3.18-150200.24.200.1	5.3.18-150200.24.200.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-obs-build	before 5.3.18-150200.24.200.1	5.3.18-150200.24.200.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-preempt	before 5.3.18-150200.24.200.1	5.3.18-150200.24.200.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-source	before 5.3.18-150200.24.200.1	5.3.18-150200.24.200.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	kernel-syms	before 5.3.18-150200.24.200.1	5.3.18-150200.24.200.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-64kb	before 5.3.18-150300.59.170.1	5.3.18-150300.59.170.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-default-base	before 5.3.18-150300.59.170.1.150300.18.100.1	5.3.18-150300.59.170.1.150300.18.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-docs	before 5.3.18-150300.59.170.2	5.3.18-150300.59.170.2
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-obs-build	before 5.3.18-150300.59.170.1	5.3.18-150300.59.170.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-preempt	before 5.3.18-150300.59.170.1	5.3.18-150300.59.170.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-source	before 5.3.18-150300.59.170.1	5.3.18-150300.59.170.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	kernel-syms	before 5.3.18-150300.59.170.1	5.3.18-150300.59.170.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-64kb	before 5.14.21-150400.24.128.1	5.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-docs	before 5.14.21-150400.24.128.1	5.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	kernel-obs-build	before 5.14.21-150400.24.128.1	5.14.21-150400.24.128.1

+96

Same product

linux: all records

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Published before and after this one in the same product

← EarlierCVE-2021-47596Jun 19, 2024 · net: hns3: fix use-after-free bug in hclgevf_send_mbx_msg
31Monitor
← EarlierCVE-2021-47597Jun 19, 2024 · inet_diag: fix kernel-infoleak for UDP sockets
22Monitor
Later →CVE-2021-47599Jun 19, 2024 · btrfs: use latest_dev in btrfs_show_devname
18Monitor

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	0d80462fbdcafd536dcad7569e65d3d14a7e9f2f	Vendor (CNA)
Linux Linux	20ad1ef02f9ad5e1dda9eeb113e4c158b4806986	Vendor (CNA)
Linux Linux	4e388232e630ebe4f94b4a0715ec98c0e2b314a3	Vendor (CNA)
Linux Linux	ab443c53916730862cec202078d36fd4008bea79	Vendor (CNA)
Linux Linux	f6deae2e2d83bd267e1986f5d71d8c458e18fd99	Vendor (CNA)
debian:linux	5.15.15-1 · Debian:12	Package registry (OSV)
opensuse:kernel-azure	5.14.21-150500.33.63.1 · openSUSE:Leap 15.5	Package registry (OSV)
opensuse:kernel-rt	5.14.21-150500.13.64.1 · openSUSE:Leap Micro 5.5	Package registry (OSV)
opensuse:kernel-rt_debug	5.14.21-150500.13.64.1 · openSUSE:Leap 15.5	Package registry (OSV)
opensuse:kernel-source-azure	5.14.21-150500.33.63.1 · openSUSE:Leap 15.5	Package registry (OSV)
opensuse:kernel-source-rt	5.14.21-150500.13.64.1 · openSUSE:Leap 15.5	Package registry (OSV)
opensuse:kernel-syms-azure	5.14.21-150500.33.63.1 · openSUSE:Leap 15.5	Package registry (OSV)
opensuse:kernel-syms-rt	5.14.21-150500.13.64.1 · openSUSE:Leap 15.5	Package registry (OSV)
suse:kernel-azure	5.14.21-150500.33.63.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5	Package registry (OSV)
suse:kernel-default	5.3.18-150200.24.200.1 · SUSE:Linux Enterprise Live Patching 15 SP2	Package registry (OSV)
suse:kernel-default-base	5.3.18-150200.24.200.1.150200.9.103.1 · SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	Package registry (OSV)
suse:kernel-docs	5.3.18-150200.24.200.1 · SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	Package registry (OSV)
suse:kernel-livepatch-SLE15-SP2_Update_51	1-150200.5.3.1 · SUSE:Linux Enterprise Live Patching 15 SP2	Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5-RT_Update_18	1-150500.11.3.1 · SUSE:Linux Enterprise Live Patching 15 SP5	Package registry (OSV)
suse:kernel-obs-build	5.3.18-150200.24.200.1 · SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	Package registry (OSV)
suse:kernel-preempt	5.3.18-150200.24.200.1 · SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	Package registry (OSV)
suse:kernel-rt	5.14.21-150500.13.64.1 · SUSE:Linux Enterprise Micro 5.5	Package registry (OSV)
suse:kernel-rt	5.3.18-150300.178.1 · SUSE:Linux Enterprise Micro 5.1	Package registry (OSV)
suse:kernel-rt_debug	5.14.21-150500.13.64.1 · SUSE:Real Time Module 15 SP5	Package registry (OSV)
suse:kernel-source	5.3.18-150200.24.200.1 · SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS	Package registry (OSV)
suse:kernel-source-azure	5.14.21-150500.33.63.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5	Package registry (OSV)
suse:kernel-source-rt	5.14.21-150500.13.64.1 · SUSE:Linux Enterprise Micro 5.5	Package registry (OSV)
suse:kernel-source-rt	5.3.18-150300.178.1 · SUSE:Linux Enterprise Micro 5.1	Package registry (OSV)
suse:kernel-syms-azure	5.14.21-150500.33.63.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5	Package registry (OSV)
suse:kernel-syms-rt	5.14.21-150500.13.64.1 · SUSE:Real Time Module 15 SP5	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).

National notice (Türkiye Cybersecurity Directorate / USOM)

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

TR-24-0733 · Jun 24, 2024(Linux Kernel Güncellemesi)

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: 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-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, 10:09 PM UTC

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

References

git.kernel.org/stable/c/0d80462fbdcafd536dcad7569e65d3d14a7e9f2f

Show all references (4 more)

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

All records