Invalid kernel reads via Unicode-map teardown race
Published Oct 28, 2026 · Updated Oct 28, 2026
Use-after-free in Linux Unicode handling allows local users to trigger invalid kernel reads during filesystem teardown. generic_ci_d_hash() and generic_ci_d_compare() dereference a Unicode map that utf8_unload() frees before existing RCU pathname lookups finish. Reachability requires casefolded filesystem lookup to race the final mount-reference release outside ordinary unmount, such as after lazy unmount; the published demonstration establishes an invalid read, not privilege escalation.
Summary
What happened
Use-after-free in Linux Unicode handling allows local users to trigger invalid kernel reads during filesystem teardown. generic_ci_d_hash() and generic_ci_d_compare() dereference a Unicode map that utf8_unload() frees before existing RCU pathname lookups finish. Reachability requires casefolded filesystem lookup to race the final mount-reference release outside ordinary unmount, such as after lazy unmount; the published demonstration establishes an invalid read, not privilege escalation.
The record
- CVE
- CVE-2026-99180
- Published
- Oct 28, 2026
- Updated
- Oct 28, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 28, 2026CVE publishedPublication date reported by the CVE source.
- Oct 28, 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=5.2
- Affected versionversion=b886ee3e778ec2ad43e276fd378ab492cf6819b7 <2b54d3c971a1e5df3c9b0bcc10311ae6c29e79d8
- Affected versionversion=b886ee3e778ec2ad43e276fd378ab492cf6819b7 <6560c3d9a6925e3747d9ad8463e16010c31ba715
- Affected versionversion=b886ee3e778ec2ad43e276fd378ab492cf6819b7 <a96c5299bd7305eb984377681eb3222a57376405
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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
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Public exploit references
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Technologies
Your stack
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Your stack
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