6.9

CVE-2025-57804: python-hyper h2 CRLF Injection

CVSS: 6.9v4.0MediumDeferred
AliasesSUSE-SU-2025:03199-1SUSE-SU-2025:03273-1SUSE-SU-2026:20187-1
Published 25-08-2025Last modified 03-11-2025
Open JSON

Vulnerability summary

CVE-2025-57804 is a medium (CVSS 6.9) CRLF Injection vulnerability in python-hyper h2. EPSS estimates a 1.73% chance of exploitation in the next 30 days, higher than 77.1% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
1.73%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 2
CGA-7G62-RJ7G-P7C6CGA-GX9P-WW82-5JV2

Timeline

  1. 25-08-2025
    PublishedVulnerability first disclosed.
  2. 03-11-2025
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

1.73%

Chance of exploitation in the next 30 days

Percentile

77%

Versus all other CVEs

30-day change

0.00 pp

From 1.73% on 19-09-2026

19-09-202619-10-2026
EPSS score
1.73%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard10 products
  • airflow-2< 2.11.0-r12
  • airflow-2-bitnami-compat< 2.11.0-r12
  • airflow-2-compat< 2.11.0-r12
  • airflow-2-iamguarded-compat< 2.11.0-r12
  • airflow-3< 3.0.6-r0
Suse6 products
  • python-h2&distro=SUSE Linux Enterprise Module for Python 3 15 SP6< 4.1.0-150400.8.6.1
  • python-h2&distro=SUSE Linux Enterprise Module for Python 3 15 SP7< 4.1.0-150400.8.6.1
  • python-h2&distro=SUSE Linux Enterprise Module for Server Applications 15 SP6< 3.2.0-150200.3.5.1
  • python-h2&distro=SUSE Linux Enterprise Module for Server Applications 15 SP7< 3.2.0-150200.3.5.1
  • python-h2&distro=SUSE Linux Enterprise Server 16.0< 4.2.0-160000.3.1
Wolfi4 products
  • airflow-3< 3.0.6-r0
  • airflow-3-bitnami-compat< 3.0.6-r0
  • airflow-3-compat< 3.0.6-r0
  • airflow-3-iamguarded-compat< 3.0.6-r0
Opensuse3 products
  • python-h2&distro=openSUSE Leap 15.6< 4.1.0-150400.8.6.1
  • python-h2&distro=openSUSE Leap 16.0< 4.2.0-160000.3.1
  • python-h2&distro=openSUSE Tumbleweed< 4.3.0-1.1
Debian1 product
  • python-h2All versions (No fix recorded) | < 4.3.0-1 | < 4.0.0-3+deb11u1
PyPI1 product
  • h2< 4.3.0
Python-hyper1 product
Ubuntu1 product
  • python-h2All versions (No fix recorded)

8 vendors · 27 products

References

16 links
Show all 16 references