{"cve":"CVE-2026-54590","nvd":{"published":"2026-07-08T21:16:49.523","modified":"2026-10-25T17:10:00.197","status":"Deferred","description":"AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in version 2.23.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","score":5.9},"cwes":["CWE-22","CWE-639"],"references":["https://github.com/ronf/asyncssh/commit/3d515ba9ba0cd9990d248bdf62bcf05d51261a88","https://github.com/ronf/asyncssh/releases/tag/v2.23.1","https://github.com/ronf/asyncssh/security/advisories/GHSA-qr67-gv47-xwwh","https://github.com/ronf/asyncssh/security/advisories/GHSA-qr67-gv47-xwwh"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:06.907763985+00:00"},"epss":{"cve":"CVE-2026-54590","score":0.00393,"percentile":0.33216,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-qr67-gv47-xwwh","url":"https://osv.dev/vulnerability/GHSA-qr67-gv47-xwwh","summary":"asyncssh has an incomplete fix for CVE-2026-45309 — AuthorizedKeysFile %u still escapes the intended directory via a leading ~ (and weakly via ${ENV}) username substitution","modified":"2026-09-10T12:25:40.597047486Z","packages":[{"ecosystem":"PyPI","name":"asyncssh","purl":"pkg:pypi/asyncssh","ranges":["<2.23.1"],"fixed":["2.23.1"]}]},{"id":"PYSEC-2026-3809","url":"https://osv.dev/vulnerability/PYSEC-2026-3809","summary":"asyncssh has an incomplete fix for CVE-2026-45309 — AuthorizedKeysFile %u still escapes the intended directory via a leading ~ (and weakly via ${ENV}) username substitution","modified":"2026-09-10T12:15:06.046808363Z","packages":[{"ecosystem":"PyPI","name":"asyncssh","purl":"pkg:pypi/asyncssh","ranges":["<2.23.1"],"fixed":["2.23.1"]}]}],"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."]}