Predictable randomness via shared post-fork vDSO state
Published Feb 18, 2026 · Updated Feb 18, 2026
Insufficient entropy in glibc's vDSO getrandom path allows context-dependent attackers to receive predictable values after a concurrent fork. Incorrect allocator ordering can leave one opaque getrandom state referenced by both a thread control block and the free-state array, causing different threads to share it after a multithreaded fork. Exposure requires an affected Linux distribution build, vDSO acceleration, and a fork concurrent with getrandom or an arc4random-family call; resulting values can undermine secrets generated from that output.
Summary
What happened
Insufficient entropy in glibc's vDSO getrandom path allows context-dependent attackers to receive predictable values after a concurrent fork. Incorrect allocator ordering can leave one opaque getrandom state referenced by both a thread control block and the free-state array, causing different threads to share it after a multithreaded fork. Exposure requires an affected Linux distribution build, vDSO acceleration, and a fork concurrent with getrandom or an arc4random-family call; resulting values can undermine secrets generated from that output.
The record
- CVE
- CVE-2025-0577
- Published
- Feb 18, 2026
- Updated
- Feb 18, 2026
- Vendor
- The GnuPG Project
- Product
- glibc
- Classifications
- CWE-331
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 18, 2026CVE publishedPublication date reported by the CVE source.
- Feb 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=2.39-28.fc40 <=2.39-33.fc40
- Affected versionversion=2.40-12.fc41 <=2.40-17.fc41
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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