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VulnerabilityPublished

CVE-2026-48985: mcdope pam_usb · NULL Pointer Dereference

Affects mcdope pam_usbSource CVE Database V5

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Not known to be exploited · CVSS 5.5 Medium : upgrade to 0.9.2 when convenient.

Data as of 1 Nov 2026, 22:58 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.9.2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.

What to do

Upgrade pam_usb and mcdope/pam_usb to 0.9.2.

Affected software

ProductAffectedFixed in
mcdopepam_usbAffected
  • <0.9.2
Fixed in
  • 0.9.2
GitHubmcdope/pam_usbpkg:github/mcdope/pam_usbOther threatsAffected
  • <0.9.2
Fixed in
  • 0.9.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade pam_usb to version 0.9.2 or later, where this NULL pointer dereference vulnerability is fixed. Patch status is confirmed by the vendor stating the issue is resolved in version 0.9.2. No other mitigation steps are indicated.

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.

References

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