CVE-2026-97587 perf: RISC-V: store available counter mask as bitmap
A local attacker can exploit a buffer overflow in the RISC-V perf subsystem to execute arbitrary code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97587?
CVE-2026-97587 is a memory corruption vulnerability in Linux, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
perf: RISC-V: store available counter mask as bitmap
The available-counter mask was a single unsigned long, but iteration uses RISCV_MAX_COUNTERS, which is 64. On RV32 that reads past the object. Filling with an unsigned-long bit at index 32 and above is also wrong.
Use DECLARE_BITMAP and set_bit/bitmap helpers. Walk each bitmap word into CFG_MATCH when checking events, when allocating an index, and when stopping all counters. Set the counter base to i times BITS_PER_LONG. Share the CFG_MATCH ecall through a small helper so the 32-bit argument split is not duplicated. On qemu-system-riscv32 the probe bitmap has bits above XLEN set, so the first word alone is not enough.
[[email protected]: updated to apply; fixed checkpatch.pl issues]
Which versions are affected by CVE-2026-97587?
How do I fix CVE-2026-97587?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-97587 being exploited?
There is no known exploitation of CVE-2026-97587 in the wild and no public exploit code.
Sources
Also known as AZL-104166, BELL-CVE-2026-97587, DEBIAN-CVE-2026-97587, GHSA-5mgm-fggv-mx2j, UBUNTU-CVE-2026-97587.