CVE-2026-48982 (GCVE-0-2026-48982)
Vulnerability from cvelistv5 – Published: 2026-06-18 19:01 – Updated: 2026-06-22 17:16
VLAI
EPSS
VEX
Title
pam_usb: Missing O_EXCL on pad temp file creation allows concurrent update race
Summary
pam_usb provides hardware authentication for Linux using ordinary removable media. In versions prior to 0.9.2, when updating a one-time pad file, a temporary file is created using open() without the O_EXCL flag. Without O_EXCL, the create operation is not atomic: two concurrent processes racing to update the same pad may both succeed in opening the file, with the second write silently overwriting the first. The one-time pad is the core replay-prevention mechanism of pam_usb. A successful race could result in the stored pad value diverging from what either process expected, potentially causing authentication failures or, in a precisely timed attack, creating a window for pad reuse. This issue has been fixed in version 0.9.2.
Severity
5.8 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-22 15:35 UTC
CWE
- CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/mcdope/pam_usb/security/adviso… | x_refsource_CONFIRM |
| https://github.com/mcdope/pam_usb/releases/tag/0.9.2 | x_refsource_MISC |
Impacted products
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