SecuriTricks - CVE-2026-55200

Description

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send crafted SSH packets with excessively large packet_length values to corrupt heap memory and achieve remote code execution.

Product(s) Impacted

Vendor	Product	Versions
Libssh2	Libssh2	<1.11.1

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-680

Integer Overflow to Buffer Overflow

The product performs a calculation to determine how much memory to allocate, but an integer overflow can occur that causes less memory to be allocated than expected, leading to a buffer overflow.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	libssh2	libssh2	<1.11.1	/	/	/	/	/	/	/

References

https://github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8

https://github.com/libssh2/libssh2/pull/2052

https://www.vulncheck.com/advisories/libssh2-out-of-bounds-write-via-unchecked-packet-length-in-transport-c

CVSS Score

9.2 / 10

CVSS Data - 4.0

Attack Vector: NETWORK
Attack Complexity: LOW
Attack Requirements: PRESENT
Privileges Required: NONE
User Interaction: NONE
Scope:
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: HIGH
Exploit Maturity: NOT_DEFINED

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/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

View Vector String

Timeline

Published: June 17, 2026, 8:17 p.m.
Last Modified: June 18, 2026, 4:17 a.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-55200