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.
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Affected Vendors & Products
References
History
Thu, 18 Jun 2026 21:30:00 +0000
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Mcdope
Mcdope pam Usb |
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| Vendors & Products |
Mcdope
Mcdope pam Usb |
Thu, 18 Jun 2026 19:45:00 +0000
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| Description | 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. | |
| Title | pam_usb: Missing O_EXCL on pad temp file creation allows concurrent update race | |
| Weaknesses | CWE-362 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-06-18T19:01:08.766Z
Reserved: 2026-05-26T23:26:07.974Z
Link: CVE-2026-48982
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OpenCVE Enrichment
Updated: 2026-06-18T21:30:16Z