OPENSUSE-SU-2026:21953-1

Vulnerability from csaf_opensuse - Published: 2026-09-23 11:56 - Updated: 2026-09-25 16:51
Summary
Security update for python-asyncssh
Severity
Moderate
Notes
Title of the patch: Security update for python-asyncssh
Description of the patch: This update for python-asyncssh fixes the following issues: Changes in python-asyncssh: - CVE-2026-62949: denial of service via infinite loop when processing zero-sized SSH packets (bsc#1280972)
Patchnames: openSUSE-Leap-16.0-packagehub-622
Terms of use: CSAF 2.0 data is provided by SUSE under the Creative Commons License 4.0 with Attribution (CC-BY-4.0).
Affected products
Product Identifier Version Remediation
Unresolved product id: openSUSE Leap 16.0:python313-asyncssh-0:2.21.0-bp160.2.1.noarch —
Vendor Fix
Threats
Impact moderate

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          "category": "general",
          "text": "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.",
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}



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