{"cve":"CVE-2026-47270","nvd":{"published":"2026-05-27T21:16:18.950","modified":"2026-10-26T12:10:00.130","status":"Deferred","description":"pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.0, pam_usb is a PAM module loaded into the host process (sudo, login, GDM, GNOME Shell). Display managers such as GDM run multiple concurrent authentication threads. Three functions used by the deny_remote feature called the non-reentrant strtok(), which stores state in a single global pointer. If two authentications race, one thread's strtok() call can overwrite the other's in-progress tokenisation pointer, causing incorrect parsing of the tmux session data or the /proc environ scan that backs the remote-session detection logic. Additionally, pusb_tmux_get_client_tty() passed the raw pointer returned by getenv(TMUX) directly to strtok(). getenv() returns a pointer into the live process environment block; strtok() inserts NUL bytes into that block, permanently corrupting the TMUX variable for subsequent code running in the same process. In long-lived display managers this affects all future authentications in that process. The combined effect can cause deny_remote=true to return an incorrect decision for a remote session, or an incorrect decision for a local session, depending on thread interleaving. This vulnerability is fixed in 0.9.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","score":6.3},"cwes":["CWE-362"],"references":["https://github.com/mcdope/pam_usb/commit/94f1640a61d49dfaf38e782680a52f01d5bf8b51","https://github.com/mcdope/pam_usb/commit/d003e551b794a9e3774ff4720830fb7aadaa48bd","https://github.com/mcdope/pam_usb/security/advisories/GHSA-j3xw-vc43-x7jg"],"products":[],"source":"nvd","synced_at":"2026-10-26T12:35:18.182177120+00:00"},"epss":{"cve":"CVE-2026-47270","score":0.00108,"percentile":0.01173,"date":"2026-10-26"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}