AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Prior to 2.23.0, AsyncSSH expands the OpenSSH-compatible AuthorizedKeysFile %u token in asyncssh/config.py, asyncssh/connection.py, asyncssh/auth_keys.py, and asyncssh/misc.py with the raw SSH username during pre-authentication server config reload, allowing a server configured with AuthorizedKeysFile authorized_keys/%u to read an authorized-keys file outside the intended directory when the SSH username contains /, \, or .. path traversal segments and authenticate with an attacker-selected key file. This issue is fixed in version 2.23.0.
CVE-2026-45309
HIGHPre-NVD 8.28.2—Trending — 3 sources updated this weekElevated
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 63% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
8.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.2Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.2
- EG Score
- 8.2(medium)
- EG Risk
- 68(Attend)EG Risk 68/100SSVC: Attend
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity82% × 45%Exploitation40% × 40%Automatability100% × 15%Action: Remediate soon — notable exploitation risk. - EPSS
- 36.9%
- KEV
- Not listed
Published
May 27, 2026
Last Modified
July 21, 2026
Advisory Details (3)
Auto-updated Jul 17, 2026Patch available. Sources: github_commit, github.
github Patch Available
AsyncSSH `AuthorizedKeysFile %u` path traversal allows attacker-selected authorized keys to authenticate a traversal username · Advisory · ronf/asyncssh · GitHub
https://github.com/ronf/asyncssh/security/advisories/GHSA-g794-3fmp-753hgithub_commit
commit 3d515ba9ba0c (ronf/asyncssh)
Fix landed in ronf/asyncssh commit 3d515ba9ba0c — awaiting tagged release
https://github.com/ronf/asyncssh/commit/3d515ba9ba0cd9990d248bdf62bcf05d51261a88github_commit
commit 2af2382cce94 (ronf/asyncssh)
Fix landed in ronf/asyncssh commit 2af2382cce94 — awaiting tagged release
https://github.com/ronf/asyncssh/commit/2af2382cce946c959a378a62f257af253dc4ab51Vendor Advisories for CVE-2026-45309(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| asyncssh | 2.22.0 | 2.23.0 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 9× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 14:18 UTCEPSS rescore
- 2026-07-23 03:16 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:24 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-17 18:55 UTCEG score recompute▲ 8.20
- 2026-07-17 18:54 UTCMITRE cvelistV5CVSS v3 → 8.2 · CVSS v4 → 8.2 · severity → HIGH
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-05-27 21:35 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-45309?
CVE-2026-45309 is a high vulnerability published on May 27, 2026. AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Prior to 2.23.0, AsyncSSH expands the OpenSSH-compatible AuthorizedKeysFile %u token in asyncssh/config.py, asyncssh/connection.py,…
When was CVE-2026-45309 disclosed?
CVE-2026-45309 was first published in the National Vulnerability Database on May 27, 2026, with the most recent update on July 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45309 actively exploited?
CVE-2026-45309 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 36.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-45309?
CVE-2026-45309 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-45309?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45309, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-45309
Is Your Infrastructure Affected by CVE-2026-45309?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.