Quick answers
- Is CVE-2026-58051 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-58051 being exploited in the wild.
- How severe is CVE-2026-58051?
- Medium severity, with a CVSS score of 6.5, published 28 June 2026.
- Which products and versions are affected?
- Libssh2 through 1.11.1.
- Is there a fix for CVE-2026-58051?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-58051 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-58051?
- Check whether you run Libssh2 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A vulnerability exists in libssh2 through version 1.11.1 due to the use of uninitialized memory in the publickey subsystem. When the library expands its publickey list using SSH2_REALLOC, it fails to zero-initialize new entries. If a malicious SSH server provides a malformed response that triggers a parsing failure, the library enters a cleanup path where libssh2_publickey_list_free attempts to free an uninitialized 'attrs' pointer. Because the value of this pointer may be influenced by previous memory contents (attacker-influenceable), this can lead to an invalid free, resulting in a denial of service or potentially remote code execution. The attack requires a client to connect to a compromised or malicious SSH server.
Affected products
- libssh2 libssh2 through 1.11.1
Timeline
- 2026-06-28: disclosed
- 2026-06-28: advisory