CVE-2026-97587

Out-of-bounds read via undersized counter bitmap

Published Sep 25, 2026 · Updated Sep 25, 2026

An out-of-bounds read in the Linux RISC-V perf PMU driver corrupts counter selection on affected RV32 systems. The driver stores a 64-counter availability mask in one unsigned long, then iterates beyond bit 31 and passes incomplete bitmap words to SBI PMU calls. The flaw requires an RV32 SBI PMU exposing higher counters; published sources establish incorrect counter handling but no attacker-controlled security consequence.

CVSS severityUnavailable
Unscored
EPSS probability0.20%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An out-of-bounds read in the Linux RISC-V perf PMU driver corrupts counter selection on affected RV32 systems. The driver stores a 64-counter availability mask in one unsigned long, then iterates beyond bit 31 and passes incomplete bitmap words to SBI PMU calls. The flaw requires an RV32 SBI PMU exposing higher counters; published sources establish incorrect counter handling but no attacker-controlled security consequence.

The record

CVE
CVE-2026-97587
Published
Sep 25, 2026
Updated
Sep 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.18
  2. Affected versionversion=e9991434596f5373dfd75857b445eb92a9253c56 <143668c424772979a45118dc9cc9c2c13a35f41d
  3. Affected versionversion=e9991434596f5373dfd75857b445eb92a9253c56 <6809da6e9c08ccc9a09cb0a48c61471679274aaa
  4. Affected versionversion=e9991434596f5373dfd75857b445eb92a9253c56 <9bec7beaed074bcae4181fde9ff9dfbe4e7b0957
  5. Affected versionversion=e9991434596f5373dfd75857b445eb92a9253c56 <e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.18; version=e9991434596f5373dfd75857b445eb92a9253c56 <143668c424772979a45118dc9cc9c2c13a35f41d; version=e9991434596f5373dfd75857b445eb92a9253c56 <6809da6e9c08ccc9a09cb0a48c61471679274aaa; version=e9991434596f5373dfd75857b445eb92a9253c56 <9bec7beaed074bcae4181fde9ff9dfbe4e7b0957; version=e9991434596f5373dfd75857b445eb92a9253c56 <e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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