Dashboard / CVE-2026-66034

CVE-2026-66034

HIGH
MEDIUM Priority: 0.03 BB Relevance: 65/100
Published: 2026-07-24 Modified: 2026-11-10 First seen: 2026-11-08 Status: active

Attack Surface

Network Low Complexity No Auth Conf. Impact Integ. Impact

CVSS Vector Breakdown

AV: Network
AC: High
PR: None
UI: Passive
S: X
AT: None
VC: High
VI: High
VA: High

Description

libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability that allows a malicious SSH server to trigger an arbitrary-length heap out-of-bounds read and a free of an uninitialized pointer via the publickey subsystem. In libssh2_publickey_list_fetch(), the version 1 response parser reads a server-controlled comment_len value and advances the parse pointer without verifying sufficient bytes remain in the buffer, causing the out-of-bounds read to leak heap pointers from adjacent allocations defeating ASLR, followed by heap allocator state corruption when the error cleanup path frees an uninitialized pointer from a non-zeroed realloc() region.

Weakness Classification (2)

Affected Software (2)

VendorProductVersion
libssh2 libssh2 < 1.11.1
libssh2 libssh2 0

References & Advisories (4)

Bug Bounty Relevance

65 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

7.7 / 10.0 v4.0
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.42%
Raw Score 0.004160
Percentile 36.4%
Date 2026-11-13

EPSS Trend

2026-11-13
0.00416
2026-11-12
0.00416
2026-11-10
0.00402
2026-11-09
0.00402
2026-11-08
0.00402

Intelligence Sources

mitre ref →
nvd ref →

External Links