File overwrite and sensitive-data disclosure via TOCTOU
Published Aug 19, 2026 · Updated Aug 19, 2026
TOCTOU race in IBM AIX 7.2 and 7.3 and PowerVM VIOS 4.1 allows local users to overwrite critical files and read sensitive data. IBM identifies bos.mp64 as affected but does not disclose the checked resource, later file operation, or attacker-controlled swap that creates the race. Exploitation requires local low-privileged access and winning a timing window; success permits critical-file modification and sensitive-data reading.
Summary
What happened
TOCTOU race in IBM AIX 7.2 and 7.3 and PowerVM VIOS 4.1 allows local users to overwrite critical files and read sensitive data. IBM identifies bos.mp64 as affected but does not disclose the checked resource, later file operation, or attacker-controlled swap that creates the race. Exploitation requires local low-privileged access and winning a timing window; success permits critical-file modification and sensitive-data reading.
The record
- CVE
- CVE-2026-16838
- Published
- Aug 19, 2026
- Updated
- Aug 19, 2026
- Vendor
- IBM
- Product
- AIX
- Classifications
- CWE-367, T1005, T1565.001
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 19, 2026CVE publishedPublication date reported by the CVE source.
- Aug 19, 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=7.2
- Affected versionversion=7.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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