CVE-2026-55199
CVE-2026-55199: 1 tracked advisory record across Red Hat. Compare vendor sources and published fix guidance.
Compare the source-linked records below. Ratings and product/version details belong to each advisory; they are not a single CVE-wide score or proof that every listed product is affected. How VulniPulse collects and checks evidence.
Vendor advisory comparison
Red Hat
1 advisory- Advisory severityMedium5.9
Medium [CVE-2026-55199] Denial of Service via crafted SSH_MSG_EXT_INFO message
CVE-2026-55199Source published Source updated
libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSH_MSG_EXT_INFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can set nr_extensions to 0xFFFFFFFF during key exchange, causing the client to spin in a tight CPU loop for over 60 seconds because return values from _libssh2_get_string() are unchecked and the session timeout does not apply to CPU-bound loops. A vulnerability in libssh2 allows a malicious SSH server to freeze connected clients during the handshake process. By triggering an infinite CPU loop during the initial connection handshake, the server can render the client unresponsive. Note: Red Hat…
- Affected products in this advisory
- Red Hat Hardened Images
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat package: libssh2
- Source-reported affected versions
- Affected-version details not available in this record.
- Source-reported fixed versions
- 1.11.1
- libssh2-main-1.11.1-8.hum1
- RHSA-2026:29950
- Mitigation guidance
- To mitigate this issue, ensure your libssh2 clients only connect to trusted SSH servers. You can enforce this by implementing outbound network access controls (egress filtering) to block applications from initiating connections to unknown or untrusted external hosts.
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