Permanent task hang via lost optimizer wakeups
Published Oct 18, 2026 · Updated Oct 18, 2026
A hang in Linux 7.0 kprobes allows local users to block optimizer-control tasks indefinitely by disabling jump optimization. In kernel/kprobes.c, the optimizer signals completion only when it is already complete, while concurrent flushers can reset the shared completion and discard an existing waiter. Triggering requires write access to the optimization controls and a jump-optimized probe; the writer and subsequent accesses to the same sysctl hang, without a demonstrated whole-system crash.
Summary
What happened
A hang in Linux 7.0 kprobes allows local users to block optimizer-control tasks indefinitely by disabling jump optimization. In kernel/kprobes.c, the optimizer signals completion only when it is already complete, while concurrent flushers can reset the shared completion and discard an existing waiter. Triggering requires write access to the optimization controls and a jump-optimized probe; the writer and subsequent accesses to the same sysctl hang, without a demonstrated whole-system crash.
The record
- CVE
- CVE-2026-98530
- Published
- Oct 18, 2026
- Updated
- Oct 18, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 18, 2026CVE publishedPublication date reported by the CVE source.
- Oct 18, 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.
- Affected versionversion=7.0
- Affected versionversion=73c12f209462d1712c5f55f3021a1b65b2e084c3 <5bfa9f1a9dcb6ecb607adbc1c0226605c972935b
- Affected versionversion=73c12f209462d1712c5f55f3021a1b65b2e084c3 <f05a01fc7d4f731b4c100d2aef1e85ad77728862
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
- Upstream kprobe optimizer hang reproducerproof of concept · demonstrated
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Technologies
Your stack
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