CVE 5.5 MEDIUM

pam_usb: NULL Dereference Crash in pusb_is_loginctl_local when loginctl Returns Empty Remote Field_CVE-2026-48985

5.5 / 10
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Description

pam_usb provides hardware authentication for Linux using ordinary removable media. In versions 0.9.1 and below, pusb_is_loginctl_local() can cause a NULL dereference crash when parsing loginctl output. The function calls popen() and reads the result; if the Remote field is only a newline, fgets() succeeds but strtok_r(buf, "\n", &saveptr) returns NULL. A subsequent strcmp(is_remote, "no") then dereferences NULL, causing undefined behavior (typically SIGSEGV) and crashing the PAM module. This can crash the authenticating process (e.g., sudo, login) and, depending on PAM stack configuration, deny access for all users of the affected service. This issue has been fixed in version 0.9.2.

Basic Information

ID CVE-2026-48985
Source GitHub_M
Published Jun 18, 2026 at 17:30
Modified Jun 18, 2026 at 19:13

Affected Product

Vendor mcdope
Product pam_usb
Version < 0.9.2
Affected Versions mcdope pam_usb < 0.9.2

CWE Classification

References

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