Vulnerability · Published May 27, 2026 · Assigned by GitHub_M

CVE-2026-44710pam_usb: NULL pointer dereference from UDisks device fields causes PAM crash and login denial-of-service

Medium 4.6

In plain English

A medium-severity null pointer dereference in pam_usb from mcdope. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities).

Severity (CVSS 3.1)4.6Medium

Exploit odds (30 days)0.2%top 92.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.8.7, src/device.c passed the return values of udisks_drive_get_serial(), udisks_drive_get_vendor(), and udisks_drive_get_model() directly to strcmp() without NULL checks. The GIO/UDisks API documentation states these accessors can return NULL for devices that do not expose the corresponding field. Passing NULL to strcmp() is undefined behaviour (typically a SIGSEGV). This vulnerability is fixed in 0.8.7.

Affected products (as reported)

Vendor	Product	Versions
mcdope	pam_usb	< 0.8.7

Weakness: CWE-476 · Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/mcdope/pam_usb/security/advisories/GHSA-j8cq-2gv6-gfwf x_refsource_CONFIRM