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No exploitation reportedAwaiting NVD analysis

CVE-2026-64669

pam_usb: deny_remote bypassed by compressed IPv6 addresses in pusb_tmux_has_remote_clients

No exploitation reported by the sources we read.

  • Published2026-11-11
  • WeaknessCWE-285 · CWE-693

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

pam_usb provides hardware authentication for Linux using removable media. From version 0.8.0 to before version 0.9.3, the deny_remote feature in pam_usb uses /usr/bin/w -i to detect whether the authenticating user has an active remote tmux session. In pusb_tmux_has_remote_clients() (src/tmux.c), the IPv6 detection regex required exactly four explicit colon-separated groups of 1-4 hex digits (e.g. 2001:0db8:85a3:0000). Any IPv6 address in compressed notation — including loopback (::1), link-local (fe80::1), and global unicast addresses (2001:db8::1) — did not match this pattern. As a result the remote-client check silently returned "no remote clients" even when a remote tmux client was connected from such an address. This issue has been patched in version 0.9.3.

Timeline

dates in UTC
  1. 2026-11-1103:52CVE publishedCNA

Versions per branch

Products declared by the CNA

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written. NVD lists no product for this CVE yet: this is the only product data so far.

  • mcdope pam_usb
    Affected
    • = >= 0.8.0, < 0.9.3no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-11

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-64669 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.17.42026-11-11
  • CNAweakness (CWE)CWE-285, CWE-6932026-11-11
  • NVDweakness (CWE)CWE-285, CWE-693read 2026-11-11

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Published
2026-11-11
Last Modified
2026-11-11
NVD status
Received

Frequently asked questions

What is CVE-2026-64669?

pam_usb provides hardware authentication for Linux using removable media. From version 0.8.0 to before version 0.9.3, the deny_remote feature in pam_usb uses /usr/bin/w -i to detect whether the authenticating user has an active remote tmux session. In pusb_tmux_has_remote_clients() (src/tmux.c), the IPv6 detection regex required exactly four explicit colon-separated groups of 1-4 hex digits (e.g. 2001:0db8:85a3:0000). Any IPv6 address in compressed notation — including loopback (::1), link-local (fe80::1), and global unicast addresses (2001:db8::1) — did not match this pattern. As a result the remote-client check silently returned "no remote clients" even when a remote tmux client was connected from such an address. This issue has been patched in version 0.9.3.

Is CVE-2026-64669 actively exploited?

Active exploitation of CVE-2026-64669 has not been confirmed.

What is the CVSS score for CVE-2026-64669?

CVE-2026-64669 has a CVSS v3 base score of 7.4 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.

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