CVE-2026-44452

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Source
https://cve.org/CVERecord?id=CVE-2026-44452
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44452.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-44452
Aliases
  • GHSA-w68q-rqwx-7wvq
Downstream
Published
2026-07-16T22:54:42Z
Modified
2026-10-28T02:31:11Z
Severity
  • 5.9 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
h2o is vulnerable to heap overrun
Details

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 8dc37cb, when h2o receives a ClientHello message over TLS or QUIC and it contains a zero-length SNI extension, the h2o server runs over the zero-length hostname while trying to copy the hostname, assuming that it is NULL-terminated. This is a potential denial-of-service attack vector in sense that it might trigger segmentation violation. This issue has been fixed by commit 8dc37cb.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-125",
        "CWE-170"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44452.json",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "range": [
                        {
                            "fixed": "8dc37cb"
                        }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                }
            ]
        }
    ]
}
References

Affected packages

Git / github.com/h2o/h2o

Affected ranges

Type
GIT
Repo
https://github.com/h2o/h2o
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
8dc37cb
Fixed
8dc37cb1e6171f7f772667618ea440696fed82c3
Database specific
Show details 
{
    "extracted_events": [
        {
            "range": [
                {
                    "introduced": "0"
                },
                {
                    "fixed": "8dc37cb"
                }
            ],
            "source": "DESCRIPTION"
        },
        {
            "range": [
                {
                    "fixed": "8dc37cb1e6171f7f772667618ea440696fed82c3"
                }
            ],
            "source": "REFERENCES_COMMIT"
        }
    ]
}
Type
GIT
Repo
https://github.com/h2oai/h2o-3
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
8dc37cb
Database specific
Show details 
{
    "extracted_events": [
        {
            "range": [
                {
                    "introduced": "0"
                },
                {
                    "fixed": "8dc37cb"
                }
            ],
            "source": "DESCRIPTION"
        }
    ]
}

Affected versions

v0.*
v0.9.1
v0.9.2
v1.*
v1.0.1
v1.1.0
v1.1.1
v1.2.0
v1.3.0
v1.3.0-beta1
v1.3.1
v1.4.0
v1.4.1
v1.4.2
v1.5.0
v1.5.0-beta1
v1.5.0-beta2
v1.5.0-beta3
v1.5.0-beta4
v1.5.1
v1.5.2
v1.5.3
v1.6.0
v1.6.0-beta1
v1.6.0-beta2
v1.7.0
v1.7.0-beta1
v1.7.0-beta2
v1.7.0-beta3
v1.7.0-beta4
v1.7.0-beta5

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44452.json"