CVE-2026-55200

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Source
https://cve.org/CVERecord?id=CVE-2026-55200
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-55200.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-55200
Downstream
Related
Published
2026-06-17T19:03:15Z
Modified
2026-08-18T18:39:14Z
Severity
  • 9.2 (Critical) CVSS_V4 - 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 CVSS Calculator
Summary
libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c
Details

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.

Database specific 
{
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
        "CWE-680"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55200.json"
}
References

Affected packages

Git / github.com/libssh2/libssh2

Affected ranges

Type
GIT
Repo
https://github.com/libssh2/libssh2
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
97acf3dfda80c91c3a8c9f2372546301d4a1a7a8
Database specific
Show details 
{
    "cpe": "cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "last_affected": "1.11.1"
        }
    ],
    "source": [
        "CPE_RANGE",
        "REFERENCES"
    ]
}

Affected versions

RELEASE.*
RELEASE.0.1
RELEASE.0.10
RELEASE.0.11
RELEASE.0.12
RELEASE.0.13
RELEASE.0.14
RELEASE.0.15
RELEASE.0.16
RELEASE.0.17
RELEASE.0.18
RELEASE.0.3
RELEASE.0.5
RELEASE.0.6
RELEASE.0.7
RELEASE.0.8
RELEASE.1.0
RELEASE.1.1
beforenb-0.*
beforenb-0.14
beforenb2-0.*
beforenb2-0.14
libssh2-1.*
libssh2-1.10.0
libssh2-1.11.0
libssh2-1.11.1
libssh2-1.2
libssh2-1.2.1
libssh2-1.2.3
libssh2-1.2.4
libssh2-1.2.5
libssh2-1.2.6
libssh2-1.2.7
libssh2-1.2.8
libssh2-1.2.9
libssh2-1.3.0
libssh2-1.4.0
libssh2-1.4.1
libssh2-1.4.2
libssh2-1.4.3
libssh2-1.5.0
libssh2-1.6.0
libssh2-1.7.0
libssh2-1.8.0
libssh2-1.9.0

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-55200.json"
vanir_signatures 
[
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "141284426602951877244048188813499579259",
                "143473284225173970337868642692660082915",
                "239476351730145920916386564352533292186",
                "186841941824073284665751444935760647525",
                "231959736810542483406341454873690778984"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-55200-959b9c2e",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8",
        "target": {
            "file": "src/transport.c"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "function_hash": "199057862071948971514444742776006168965",
            "length": 7507
        },
        "id": "CVE-2026-55200-a735b935",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8",
        "target": {
            "file": "src/transport.c",
            "function": "ssh2_transport_read"
        }
    }
]
vanir_signatures_modified 
"2026-08-18T18:39:14Z"