UBUNTU-CVE-2025-57804 (CVE-2025-57804)
Vulnerability from osv_ubuntu – Published: 2025-08-25 21:15 – Updated: 2026-05-20 15:22 – Source website
VLAI
Details
h2 is a pure-Python implementation of a HTTP/2 protocol stack. Prior to version 4.3.0, an HTTP/2 request splitting vulnerability allows attackers to perform request smuggling attacks by injecting CRLF characters into headers. This occurs when servers downgrade HTTP/2 requests to HTTP/1.1 without properly validating header names/values, enabling attackers to manipulate request boundaries and bypass security controls. This issue has been patched in version 4.3.0.
Severity
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python-h2",
"binary_version": "3.0.1-3"
},
{
"binary_name": "python3-h2",
"binary_version": "3.0.1-3"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "python-h2",
"purl": "pkg:deb/ubuntu/python-h2@3.0.1-3?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.0.1-1",
"3.0.1-2",
"3.0.1-3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-h2",
"binary_version": "3.1.1-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "python-h2",
"purl": "pkg:deb/ubuntu/python-h2@3.1.1-1?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.0.1-4",
"3.0.1-4.1ubuntu1",
"3.0.1-5",
"3.1.1-1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-h2",
"binary_version": "4.1.0-3ubuntu1"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "python-h2",
"purl": "pkg:deb/ubuntu/python-h2@4.1.0-3ubuntu1?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"4.0.0-3",
"4.1.0-3ubuntu1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-h2",
"binary_version": "4.1.0-4"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "python-h2",
"purl": "pkg:deb/ubuntu/python-h2@4.1.0-4?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"4.1.0-4"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-h2",
"binary_version": "4.2.0-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "python-h2",
"purl": "pkg:deb/ubuntu/python-h2@4.2.0-1?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"4.1.0-4",
"4.2.0-1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-h2",
"binary_version": "4.3.0-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "python-h2",
"purl": "pkg:deb/ubuntu/python-h2@4.3.0-1?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"4.2.0-1",
"4.3.0-1"
]
}
],
"aliases": [],
"details": "h2 is a pure-Python implementation of a HTTP/2 protocol stack. Prior to version 4.3.0, an HTTP/2 request splitting vulnerability allows attackers to perform request smuggling attacks by injecting CRLF characters into headers. This occurs when servers downgrade HTTP/2 requests to HTTP/1.1 without properly validating header names/values, enabling attackers to manipulate request boundaries and bypass security controls. This issue has been patched in version 4.3.0.",
"id": "UBUNTU-CVE-2025-57804",
"modified": "2026-05-20T15:22:56Z",
"published": "2025-08-25T21:15:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2025-57804"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2025-57804"
},
{
"type": "REPORT",
"url": "https://github.com/python-hyper/h2/security/advisories/GHSA-847f-9342-265h"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N",
"type": "CVSS_V4"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2025-57804"
]
}
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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.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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