What’s Vulnerable › Vulnerabilities

CVE-2026-48066: pam_usb: Thread-unsafe static pointer in log.c causes data race under concurrent PAM authentication

• Severity: medium (CVSS 5.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-27 · updated 2026-10-26
• Weakness: CWE-362

Description

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, src/log.c contains a process-wide static pointer that is written on every PAM invocation with the address of a stack-local variable. This violates the PAM re-entrancy requirement and creates a data race when the PAM stack is invoked concurrently from multiple threads. This vulnerability is fixed in 0.9.1.

Affected products

• mcdope pam_usb: before 0.9.1

References

• https://github.com/mcdope/pam_usb/issues/350
• https://github.com/mcdope/pam_usb/issues/55
• https://github.com/mcdope/pam_usb/security/advisories/GHSA-qg76-57wq-mpv6

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