CVE-2026-74637
- Source
- https://cve.org/CVERecord?id=CVE-2026-74637
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74637.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-74637
- Downstream
- Published
- 2026-08-22T15:32:16Z
- Modified
- 2026-08-28T03:47:18Z
- Severity
-
- 7.8 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
- Summary
- perf/core: Fix group leader use-after-free after sibling detach
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
perf/core: Fix group leader use-after-free after sibling detach
perf_group_detach() handles leader and sibling detach differently. When the group leader is detached, all siblings are promoted to singleton events and their group_leader pointer is reset to themselves. When a sibling is detached, it is removed from the leader's sibling_list, but its group_leader pointer is left pointing at the old leader.
That is harmless when the sibling is being closed and freed immediately, as in the DETACH_DEAD path. It is not safe when the sibling is detached but kept alive, such as during CPU hotplug with DETACH_GROUP. In that case the sibling is removed from the context, while its file descriptor can still keep it alive.
A typical failing sequence is:
- A group contains leader L and sibling S.
- CPU hot-unplug detaches S with DETACH_GROUP, removing it from L->sibling_list but leaving S->group_leader == L.
- L is later closed and freed.
- A PERF_IOC_FLAG_GROUP ioctl on S follows S->group_leader and dereferences the freed leader.
This was reproduced by running the perf event fuzzer, CPU hotplug, and a stress workload concurrently:
Unable to handle kernel paging request at virtual address 006b6b6b6b6b6cdb CPU: 2 PID: 12489 Comm: perf_fuzzer 6.18.7 PREEMPT pc : perf_ioctl+0x34c/0xc68 x20: ffffff89a3fa2c70 x8 : 6b6b6b6b6b6b6b6b Code: 943c4a0e 340047a0 f9404a94 f9411e88 (f940b908) Call trace: perf_ioctl+0x34c/0xc68 (P) __arm64_sys_ioctl+0xa0/0xf4 invoke_syscall+0x58/0xe4 el0_svc_common+0xa8/0xdc do_el0_svc+0x1c/0x28 el0_svc+0x40/0xc0 el0t_64_sync_handler+0x68/0xdc el0t_64_sync+0x1c4/0x1c8
The fault happened in perf_ioctl(), where perf_event_for_each() follows the stale group_leader pointer and perf_event_for_each_child() then dereferences the freed leader's context.
Fix the use-after-free by promoting the detached sibling to a singleton. Also fix __event_disable() cgroup accounting and event state change.
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74637.json" }- References
-
- https://git.kernel.org/stable/c/1e7abfeb23c12bf46f6457e4a3e1a1a300d50619
- https://git.kernel.org/stable/c/42c5ca1f0a288a52878bd72a5595b08261057438
- https://git.kernel.org/stable/c/80c6054a4c40a0ffad82acef9f9a0dee108d152a
- https://git.kernel.org/stable/c/8e92e03984364d93e0d5b0acd81c95eca773f034
- https://git.kernel.org/stable/c/8f867c0e8da4c2303d91adf45acb6b1820966c27
- https://git.kernel.org/stable/c/a979a642402d0b1f856c7a729b4cb2d92de4cf2f
- https://git.kernel.org/stable/c/b42948f9e0d1ea4dbd5742ce1dfc7688de5d4a35
- https://git.kernel.org/stable/c/f8a07021679aadfb6d63b209207ccc41f26982d1
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74637.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-74637
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8a49542c0554af7d0073aac0ee73ee65b807ef34Fixed8f867c0e8da4c2303d91adf45acb6b1820966c27Fixed8e92e03984364d93e0d5b0acd81c95eca773f034Fixedf8a07021679aadfb6d63b209207ccc41f26982d1Fixed80c6054a4c40a0ffad82acef9f9a0dee108d152aFixedb42948f9e0d1ea4dbd5742ce1dfc7688de5d4a35Fixeda979a642402d0b1f856c7a729b4cb2d92de4cf2fFixed1e7abfeb23c12bf46f6457e4a3e1a1a300d50619Fixed42c5ca1f0a288a52878bd72a5595b08261057438
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedLast Affectede732ebc42aea321ee84514330eb3a675307fcc83
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2.6.34.14Fixed2.6.35
Affected versions
v2.*
Linux / Kernel
Package
- Name
- Kernel
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced2.6.35Fixed5.10.267
- Type
- ECOSYSTEM
- Events
-
Introduced5.11.0Fixed5.15.218
- Type
- ECOSYSTEM
- Events
-
Introduced5.16.0Fixed6.1.185
- Type
- ECOSYSTEM
- Events
-
Introduced6.2.0Fixed6.6.154
- Type
- ECOSYSTEM
- Events
-
Introduced6.7.0Fixed6.12.105
- Type
- ECOSYSTEM
- Events
-
Introduced6.13.0Fixed6.18.45
- Type
- ECOSYSTEM
- Events
-
Introduced6.19.0Fixed7.1.9