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UnratedPublic exploit

Free of Uninitialized Pointer in libssh2 Publickey List Cleanup

IdentifiersCVE-2026-58051CWE-824

CVE-2026-58051 is a memory-safety vulnerability in libssh2 through version 1.11.1. When libssh2 expands its publickey list using SSH2_REALLOC, newly allocated entries are not zero-initialized before parser logic populates them. If parsing of a publickey subsystem response fails before initialization completes, execution can reach the cleanup path with one or more partially initialized or uninitialized entries still present. In that state, libssh2_publickey_list_free may operate on an uninitialized entry and free an uninitialized, attacker-influenceable attrs pointer. A malicious SSH server offering the publickey subsystem can trigger this condition by sending a malformed response to a connecting libssh2 client.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can cause client-side memory corruption when libssh2 frees an uninitialized pointer during cleanup. The most direct impact is process instability or denial of service in applications using vulnerable libssh2 clients. Because the freed pointer is described as attacker-influenceable, there is also potential for more serious exploitation depending on allocator behavior, memory layout, and application context, though the provided information does not confirm reliable code execution.

Mitigation

If you can’t patch tonight, do this now.

Until patched versions are deployed, avoid connecting libssh2-based clients to untrusted or attacker-controlled SSH servers. If operationally feasible, disable or avoid use of the affected publickey subsystem in workflows that do not require it, and reduce exposure by limiting outbound connections to trusted SSH endpoints only.

Remediation

Patch, then assume compromise.

Upgrade libssh2 to a fixed release newer than 1.11.1 that correctly initializes newly grown publickey list entries before they are used and ensures cleanup paths handle parse failures safely. The available guidance specifically recommends zero-initializing all new entries in the publickey list and validating cleanup logic for memory safety.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Libssh2Libssh2application

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

7 SOURCESView more in app
What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity6

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-58051
NVD
nvd.nist.gov/vuln/detail/CVE-2026-58051
MITRE CWE · CWE-824
cwe.mitre.org