python-hyper h2 up to 4.2.x HTTP/2 crlf injection

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, was found in python-hyper h2 up to 4.2.x. Affected is an unknown function of the component HTTP2 Handler. Such manipulation leads to crlf injection. This vulnerability is documented as CVE-2025-57804. The attack can be executed remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in python-hyper h2 up to 4.2.x and classified as problematic. Affected by this issue is some unknown functionality of the component HTTP2 Handler. The manipulation with an unknown input leads to a crlf injection vulnerability. Using CWE to declare the problem leads to CWE-93. The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs. Impacted is integrity. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2025-57804 since 08/20/2025. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available.

The vulnerability scanner Nessus provides a plugin with the ID 264670 (SUSE SLED15 / SLES15 / openSUSE 15 Security Update : python-h2 (SUSE-SU-2025:03199-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.3.0 eliminates this vulnerability. Applying the patch 035e9899f95e3709af098f578bfc3cd302298e3a is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (264670). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Crlf injection
CWE: CWE-93 / CWE-74 / CWE-707
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 264670
Nessus Name: SUSE SLED15 / SLES15 / openSUSE 15 Security Update : python-h2 (SUSE-SU-2025:03199-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: h2 4.3.0
Patch: 035e9899f95e3709af098f578bfc3cd302298e3a

Timelineinfo

08/20/2025 CVE reserved
08/26/2025 +6 days Advisory disclosed
08/26/2025 +0 days VulDB entry created
09/13/2025 +18 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-847f-9342-265h
Status: Confirmed

CVE: CVE-2025-57804 (🔒)
GCVE (CVE): GCVE-0-2025-57804
GCVE (VulDB): GCVE-100-321386

Entryinfo

Created: 08/26/2025 04:44
Updated: 09/13/2025 16:18
Changes: 08/26/2025 04:44 (71), 09/13/2025 16:18 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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