{"api_version":"1","generated_at":"2026-05-28T15:54:17+00:00","cve":"CVE-2026-47270","urls":{"html":"https://cve.report/CVE-2026-47270","api":"https://cve.report/api/cve/CVE-2026-47270.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-47270","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-47270"},"summary":{"title":"pam_usb: strtok() race condition in multi-threaded PAM hosts can corrupt deny_remote result","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.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-05-27 21:16:18","updated_at":"2026-05-28 13:57:25"},"problem_types":["CWE-362","CWE-362 CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"6.3","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","baseScore":6.3,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"6.3","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","data":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/mcdope/pam_usb/commit/d003e551b794a9e3774ff4720830fb7aadaa48bd","name":"https://github.com/mcdope/pam_usb/commit/d003e551b794a9e3774ff4720830fb7aadaa48bd","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/mcdope/pam_usb/security/advisories/GHSA-j3xw-vc43-x7jg","name":"https://github.com/mcdope/pam_usb/security/advisories/GHSA-j3xw-vc43-x7jg","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/mcdope/pam_usb/commit/94f1640a61d49dfaf38e782680a52f01d5bf8b51","name":"https://github.com/mcdope/pam_usb/commit/94f1640a61d49dfaf38e782680a52f01d5bf8b51","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-47270","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47270","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"mcdope","product":"pam_usb","version":"affected < 0.9.0","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-47270","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","timestamp":"2026-05-28T13:25:20.725360Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-05-28T13:25:31.065Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"pam_usb","vendor":"mcdope","versions":[{"status":"affected","version":"< 0.9.0"}]}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","description":"CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-05-27T20:10:37.108Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/mcdope/pam_usb/security/advisories/GHSA-j3xw-vc43-x7jg","tags":["x_refsource_CONFIRM"],"url":"https://github.com/mcdope/pam_usb/security/advisories/GHSA-j3xw-vc43-x7jg"},{"name":"https://github.com/mcdope/pam_usb/commit/94f1640a61d49dfaf38e782680a52f01d5bf8b51","tags":["x_refsource_MISC"],"url":"https://github.com/mcdope/pam_usb/commit/94f1640a61d49dfaf38e782680a52f01d5bf8b51"},{"name":"https://github.com/mcdope/pam_usb/commit/d003e551b794a9e3774ff4720830fb7aadaa48bd","tags":["x_refsource_MISC"],"url":"https://github.com/mcdope/pam_usb/commit/d003e551b794a9e3774ff4720830fb7aadaa48bd"}],"source":{"advisory":"GHSA-j3xw-vc43-x7jg","discovery":"UNKNOWN"},"title":"pam_usb: strtok() race condition in multi-threaded PAM hosts can corrupt deny_remote result"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-47270","datePublished":"2026-05-27T20:10:37.108Z","dateReserved":"2026-05-18T23:03:37.229Z","dateUpdated":"2026-05-28T13:25:31.065Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-27 21:16:18","lastModifiedDate":"2026-05-28 13:57:25","problem_types":["CWE-362","CWE-362 CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","baseScore":6.3,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":1,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"47270","Ordinal":"1","Title":"pam_usb: strtok() race condition in multi-threaded PAM hosts can","CVE":"CVE-2026-47270","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"47270","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"pam_usb: strtok() race condition in multi-threaded PAM hosts can"}]}}}