CVSS 3.1
8.8 highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVE-2026-102643
High (8.8) in ronf asyncssh. EPSS 0.8% estimated probability of exploitation activity in the next 30 days.
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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 2.24.1, SFTPServer.map_path() uses posixpath.normpath() on a client-supplied path and removes only one leading slash before passing the result to posixpath.join() with the configured chroot. An authenticated SFTP user can supply a path beginning with exactly two slash characters, causing POSIX normalization to preserve the double-leading-slash form and the subsequent join to treat the remaining pathname as absolute. This bypasses the SFTP chroot and permits reads and writes with the operating-system permissions of the account running the server, which may enable code execution depending on writable targets. This issue is fixed in version 2.24.1.
Severity
- EPSS
- 0.8% estimated probability of exploitation activity in the next 30 days; 58th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
- CWEs
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory (Path traversal)
CWE-50 Path Equivalence: '//multiple/leading/slash' - OWASP Top 10
- A01:2025 Broken Access Control
- Published
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Not in the NVD yet
- Record from
- the CVE List, synced
Ask an AI about this CVE
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Explain CVE-2026-102643 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-102643?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-102643?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-102643 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| ronf asyncssh | < 2.24.1 |
Attack patterns (CAPEC)
- CAPEC-64 Using Slashes and URL Encoding Combined to Bypass Validation Logic Likelihood: High · Severity: High
- CAPEC-76 Manipulating Web Input to File System Calls Likelihood: High · Severity: Very High
- CAPEC-78 Using Escaped Slashes in Alternate Encoding Likelihood: High · Severity: High
- CAPEC-79 Using Slashes in Alternate Encoding Likelihood: High · Severity: High
- CAPEC-126 Path Traversal Likelihood: High · Severity: Very High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.