Bug 2494414

Summary: CVE-2026-58051 libssh2: libssh2: Denial of service or information disclosure via malformed SSH publickey response [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Srikanth Balasubramanian <sbalasub>
Component: libssh2Assignee: Paul Howarth <paul>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: epel10CC: kdudka, paul
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["f8c548b8-2b06-47d2-99d3-8d2bd14454fd"]}
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2493950    

Description Srikanth Balasubramanian 2026-06-29 14:43:01 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries before parsing populates them, so a parse failure reaching the cleanup path leaves libssh2_publickey_list_free operating on an uninitialized entry. A malicious SSH server offering the publickey subsystem can use a malformed response to make cleanup free an uninitialized, attacker-influenceable attrs pointer in a connecting libssh2 client.