CVE-2026-48985: medium-severity vulnerability in mcdope pam_usb
pam_usb: NULL Dereference Crash in pusb_is_loginctl_local when loginctl Returns Empty Remote Field
Published
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.5epss 0.2%
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.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected products
mcdope · pam_usbRelated CVEs — mcdope pam_usb
In the same product, most dangerous first.
CVE-2026-64669HIGHpam_usb: deny_remote bypassed by compressed IPv6 addresses in pusb_tmux_has_remote_clientsEPSS 0.4%CVE-2026-64668HIGHpam_usb: deny_remote bypassed by zone-indexed IPv6 addresses (fe80::1%eth0) in pusb_tmux_has_remote_clientsEPSS 0.4%CVE-2026-48064HIGHpam_usb: PAM_RHOST check skipped when deny_remote=false allows XDMCP authentication bypassEPSS 0.3%CVE-2026-47269HIGHpam_usb: deny_remote feature incorrectly classifies IPv4-mapped IPv6 remote connections as localEPSS 0.3%CVE-2026-47273MEDIUMpam_usb: XPath injection via PAM-supplied identifiers in pam_usb configuration queriesEPSS 0.3%CVE-2026-44711HIGHpam_usb: Symlink attacks on pad directory and pad files enable authentication bypass and root file corruptionEPSS 0.2%