[NEW] [high] libssh2: Multiple vulnerabilities

highCVE-2026-66032 CVE-2026-66033 CVE-2026-66034 CVE-2026-66035

A remote, anonymous attacker can exploit multiple vulnerabilities in libssh2 to potentially disclose confidential information, cause a Denial-of-Service condition, or execute arbitrary code.

CSIRTS triage

vendor: libssh2 product: libssh2 Information disclosure Denial of service Remote code execution

What: Multiple vulnerabilities can be exploited by a remote, anonymous attacker to disclose confidential information, cause a Denial-of-Service condition, or execute arbitrary code.
Who is affected: Deployments of libssh2.
Urgency: Remediation is high urgency due to the severity and potential for exploitation.
Action: Update to the latest version of libssh2 immediately.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CERT-Bund (BSI) Security Advisories (DE · national-cert · site)
Severity: high
Published: 2026-07-28
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-2516

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-2026-660320.29% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 21% of all scored CVEs.
Low exploitation riskCVE-2026-660330.37% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 30% of all scored CVEs.
Low exploitation riskCVE-2026-660340.25% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 17% of all scored CVEs.
Low exploitation riskCVE-2026-660350.32% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 24% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-66032	coverage & exploitation status	NVD · CVE.org
CVE-2026-66033	coverage & exploitation status	NVD · CVE.org
CVE-2026-66034	coverage & exploitation status	NVD · CVE.org
CVE-2026-66035	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for libssh2

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

medium[UPDATE] [medium] libssh2: Multiple vulnerabilitiescert-bund · 2026-07-28
highCVE-2026-66035: libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer ove…nvd · 2026-07-24
highCVE-2026-66034: libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability…nvd · 2026-07-24
highCVE-2026-66033: libssh2 through 1.11.1, fixed in commit a2ed82d, contains a pre-authentication integer underfl…nvd · 2026-07-24
highCVE-2026-66032: libssh2 through 1.11.1, fixed in commit 5e47761, contains a double-free vulnerability in the s…nvd · 2026-07-24
high[UPDATE] [high] libssh2: Multiple vulnerabilitiescert-bund · 2026-07-17