HIGHpublic-safe

CVE-2026-66035

NVD: libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer overflow vulnerability that allows a malicious SSH server to corrupt heap metadata in any connecting client by sending a packet with a packet_length smaller than the... NVD: In the fullpacket() function in src/transport.c, the ETM path allocates a buffer of packet_length bytes but copies blocksize minus one bytes via memcpy, causing an overflow that on 32-bit glibc writes attacker-controlled bytes into an adjacent chunk's SIZE... OSV: libssh2 Heap Buffer Overflow via ETM Cipher Negotiation

CVSS
7.7 Severity
HIGH EPSS
0.0032 (24) KEV
-

Source-published summary

Possible impact

Source describes memory safety review. Possible impact: The affected component has memory-safety risk that may lead to crash, privilege, or code-execution impact depending on exposure.

Affected context

vendor/product: libssh2 / libssh2

Remediation / advisory

Patch confirmed by source text; fixed version context: commit.

Why it matters

Source describes memory safety review. Possible impact: The affected component has memory-safety risk that may lead to crash, privilege, or code-execution impact depending on exposure.; CVSS 7.7 (HIGH); EPSS percentile 24; not listed in KEV; Patch confirmed by source text; fixed version context: commit; sources: NVD, OSV.

What to verify

Confirm affected product/version, vendor advisory, patch or mitigation, and exposure.

Exposure hint

exposure unknown

Impact tags

memory safety review

Urgency reasons

CVSS HIGHaffected product presentvendor advisory presentrecent updateremediation reference present

Source-derived note

Summary derived from NVD / OSV description; unsafe procedural detail is not shown.

Redaction metadata

source summary used: True
fallback summary used: False
unsafe procedural detail present: false
raw source displayed: false
public summary redacted: true

Remediation handoff

Public-safe static handoff for human/Codex remediation planning. Scan, patch, external execution, and auto remediation are disabled.

Handoff JSON Handoff Markdown Safe Codex prompt

Safety note

This radar shows source-published defensive context only. Exploit procedures, exploit strings, scanner commands, and auto-remediation are not provided.