VulnerabilityPublished 25 Sep 2026Updated 21 Oct 2026

CVE-2026-97587: Linux kernel · perf: RISC-V: store available counter mask as bitmap

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb, 143668c424772979a45118dc9cc9c2c13a35f41d, 6809da6e9c08ccc9a09cb0a48c61471679274aaa +2

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ e9991434596f5373dfd75857b445eb92a9253c56, < e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb	Fixed in e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb
LinuxLinux	Affected ≥ e9991434596f5373dfd75857b445eb92a9253c56, < 143668c424772979a45118dc9cc9c2c13a35f41d	Fixed in 143668c424772979a45118dc9cc9c2c13a35f41d
LinuxLinux	Affected ≥ e9991434596f5373dfd75857b445eb92a9253c56, < 6809da6e9c08ccc9a09cb0a48c61471679274aaa	Fixed in 6809da6e9c08ccc9a09cb0a48c61471679274aaa
LinuxLinux	Affected ≥ e9991434596f5373dfd75857b445eb92a9253c56, < 9bec7beaed074bcae4181fde9ff9dfbe4e7b0957	Fixed in 9bec7beaed074bcae4181fde9ff9dfbe4e7b0957
LinuxLinux	Affected ≥ e9991434596f5373dfd75857b445eb92a9253c56, < 5a1b6379eed5b13eac0228b605b0bed988e547e9	Fixed in 5a1b6379eed5b13eac0228b605b0bed988e547e9
LinuxLinux	Affected =5.18	Fixed in–

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. [pjw@kernel.org: updated to apply; fixed checkpatch.pl issues]

References

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