Linux Kernel perf: PMU Context Out-of-Bounds Memory Access (CVE-2026-31528)
CVE-2026-31528 Published on April 22, 2026
perf: Make sure to use pmu_ctx->pmu for groups
In the Linux kernel, the following vulnerability has been resolved:
perf: Make sure to use pmu_ctx->pmu for groups
Oliver reported that x86_pmu_del() ended up doing an out-of-bound memory access
when group_sched_in() fails and needs to roll back.
This *should* be handled by the transaction callbacks, but he found that when
the group leader is a software event, the transaction handlers of the wrong PMU
are used. Despite the move_group case in perf_event_open() and group_sched_in()
using pmu_ctx->pmu.
Turns out, inherit uses event->pmu to clone the events, effectively undoing the
move_group case for all inherited contexts. Fix this by also making inherit use
pmu_ctx->pmu, ensuring all inherited counters end up in the same pmu context.
Similarly, __perf_event_read() should use equally use pmu_ctx->pmu for the
group case.
Products Associated with CVE-2026-31528
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Affected Versions
Linux:- Version bd27568117664b8b3e259721393df420ed51f57b and below 656f35b463995bee024d948440128230aacd81e1 is affected.
- Version bd27568117664b8b3e259721393df420ed51f57b and below 3a696e84a8b1fafdd774bb30d62919faf844d9e4 is affected.
- Version bd27568117664b8b3e259721393df420ed51f57b and below 35f7914e54fe7f13654c22ee045b05e4b6d8062b is affected.
- Version bd27568117664b8b3e259721393df420ed51f57b and below 4c759446046500a1a6785b25725725c3ff087ace is affected.
- Version bd27568117664b8b3e259721393df420ed51f57b and below 4b9ce671960627b2505b3f64742544ae9801df97 is affected.
- Version 6.2 is affected.
- Before 6.2 is unaffected.
- Version 6.6.131, <= 6.6.* is unaffected.
- Version 6.12.80, <= 6.12.* is unaffected.
- Version 6.18.21, <= 6.18.* is unaffected.
- Version 6.19.11, <= 6.19.* is unaffected.
- Version 7.0, <= * is unaffected.