DEBIAN-CVE-2026-62949
- Source
- https://security-tracker.debian.org/tracker/CVE-2026-62949
- Import Source
- https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-62949.json
- JSON Data
- https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-62949
- Upstream
- Published
- 2026-09-16T20:17:26Z
- Modified
- 2026-09-18T17:00:06Z
- Severity
-
- 6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
- Summary
- [none]
- Details
-
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 2.24.0, _process_channel_open and _process_channel_open_confirmation in asyncssh/connection.py accept a peer-supplied send_pktsize value of zero. When channel data reaches SSHChannel._flush_send_buf in asyncssh/channel.py, the zero value causes each loop iteration to slice and remove zero bytes without reducing the send window, leaving the synchronous loop permanently true with no await point. A malicious SSH server can trigger the client path through SSH_MSG_CHANNEL_OPEN_CONFIRMATION before the first channel write, while an authenticated client can trigger the server path through SSH_MSG_CHANNEL_OPEN and freeze every current and future connection handled by the process. This vulnerability is fixed in 2.24.0.
- References
Affected packages
Debian:12 / python-asyncssh
Package
- Name
- python-asyncssh
- Purl
- pkg:deb/debian/python-asyncssh?arch=source&distro=bookworm
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affected
Debian:13 / python-asyncssh
Package
- Name
- python-asyncssh
- Purl
- pkg:deb/debian/python-asyncssh?arch=source&distro=trixie
Debian:14 / python-asyncssh
Package
- Name
- python-asyncssh
- Purl
- pkg:deb/debian/python-asyncssh?arch=source&distro=forky