CVE-2026-55200 (GCVE-0-2026-55200)

Vulnerability from cvelistv5 – Published: 2026-06-17 19:03 – Updated: 2026-06-18 11:46 X_Open Source
VLAI
Title
libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c
Summary
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.
Severity
9.2 (Critical)
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
8.1 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
  • CWE-680 - Integer Overflow to Buffer Overflow
Assigner
References
Impacted products
Vendor Product Version
libssh2 libssh2 Affected: 0 , ≤ 1.11.1 (semver)
Unaffected: 7acf3dfda80c91c3a8c9f2372546301d4a1a7a8 (git)
Create a notification for this product.
Date Public
2026-06-12 00:00
Credits
Tristan Madani (@TristanInSec)
Show details on NVD website
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.