CVE-2026-31528
Published: 22 April 2026
Summary
CVE-2026-31528 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 2.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and RA-5 (Vulnerability Monitoring and Scanning).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly and comprehensively mitigates CVE-2026-31528 by requiring timely patching of the Linux kernel with commits that ensure consistent pmu_ctx->pmu usage in perf event inheritance, group scheduling, and reading.
Addresses the vulnerability by scanning for and identifying the known Linux kernel perf out-of-bounds access flaw, enabling remediation.
Mitigates exploitation of the out-of-bounds memory access in the kernel perf subsystem through enforced memory protection mechanisms.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel OOB memory access in perf enables direct privilege escalation via memory modification (T1068), credential harvesting via arbitrary reads (T1212), and system crashes for DoS (T1499.004).
NVD Description
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…
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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.
Deeper analysisAI
CVE-2026-31528 is a vulnerability in the Linux kernel's perf subsystem that leads to an out-of-bounds memory access. The issue occurs in x86_pmu_del() during rollback when group_sched_in() fails, particularly when the group leader is a software event. This stems from transaction handlers using the wrong PMU, as inherit clones events with event->pmu instead of pmu_ctx->pmu, undoing prior fixes in move_group and group_sched_in cases. Similarly, __perf_event_read() fails to use pmu_ctx->pmu for groups. It is classified as CWE-125 with a CVSS v3.1 base score of 7.8.
A local attacker with low privileges can exploit this vulnerability with low attack complexity and no user interaction required. Successful exploitation grants high impacts on confidentiality, integrity, and availability, potentially allowing arbitrary kernel memory reads, modifications, or crashes due to the out-of-bounds access.
Mitigation requires applying upstream kernel patches, as detailed in the referenced stable commits: 35f7914e54fe7f13654c22ee045b05e4b6d8062b, 3a696e84a8b1fafdd774bb30d62919faf844d9e4, 4b9ce671960627b2505b3f64742544ae9801df97, 4c759446046500a1a6785b25725725c3ff087ace, and 656f35b463995bee024d948440128230aacd81e1. These ensure consistent use of pmu_ctx->pmu in inherit and __perf_event_read() for group cases.
Details
- CWE(s)