CVE-2026-55200
libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c
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.
INFO
Published Date :
June 17, 2026, 7:03 p.m.
Last Modified :
June 17, 2026, 7:03 p.m.
Remotely Exploit :
Yes !
Source :
VulnCheck
Affected Products
The following products are affected by CVE-2026-55200
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | CRITICAL | 83251b91-4cc7-4094-a5c7-464a1b83ea10 |
Solution
- Update libssh2 to a patched version.
- Apply the fix from commit 7acf3df.
- Validate packet length checks.
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CVE-2026-55200 vulnerability anywhere in the article.