USN-8532-1: libssh2 vulnerabilities
It was discovered that libssh2 incorrectly handled certain publickey subsystem attributes. A remote attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2026-58050) It was discovered that libssh2 did not properly initialize publickey list entries before parsing. A remote attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2026-58051)
CSIRTS triage
- What
- libssh2 has vulnerabilities that could allow a remote attacker to cause denial of service or execute arbitrary code.
- Who is affected
- Users of libssh2 in environments where it interacts with malicious SSH servers.
- Urgency
- Remediation is urgent due to the potential for remote code execution and denial of service.
- Action
- Update to the latest version of libssh2 to mitigate these vulnerabilities.
AI-assisted analysis generated from the source advisory — verify against the original.
⚡ Watch libssh2
Get an email when a new libssh2 advisory drops — max one per day, one-click unsubscribe.
Details
Original advisory: https://ubuntu.com/security/notices/USN-8532-1
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-580500.36% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 29% of all scored CVEs.
- Low exploitation riskCVE-2026-580510.28% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 20% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-58050 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-58051 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- medium[UPDATE] [medium] libssh2: Multiple vulnerabilitiescert-bund
- mediumCVE-2026-58051: libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize…nvd
- highCVE-2026-58050: libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-su…nvd
- mediumCVE-2026-58051: libssh2 - Free of Uninitialized Pointer in publickey List Cleanupmsrc
- highCVE-2026-58050: libssh2 - Integer Overflow in publickey Subsystem Attribute Allocationmsrc
More from Ubuntu Security Notices
- highUSN-8620-4: Linux kernel (Intel IoTG) vulnerabilities2026-07-31
- highUSN-8620-3: Linux kernel (Intel IoTG) vulnerabilities2026-07-31
- unknownUSN-8625-1: OpenSSL vulnerability2026-07-30
- unknownUSN-8624-1: Sinatra vulnerability2026-07-29
- unknownUSN-8623-1: Linux kernel (NVIDIA) vulnerabilities2026-07-29