CVE-2025-49630

Apache HTTP Server: mod_proxy_http2 denial of service

Published Jul 10, 2025 CVSS 3.1 · 7.5 High EPSS 1.4% KEV · Not listed
Description
In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.

Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4270-1 apache2 security update
EUVD EUVD EUVD-2025-21017 In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2. Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".
Ubuntu USN Ubuntu USN USN-7639-1 Apache HTTP Server vulnerabilities
Ubuntu USN Ubuntu USN USN-7639-2 Apache HTTP Server vulnerabilities
History
Type Values Removed Values Added
First Time appeared Apache http Server
CPEs cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
Vendors & Products Apache http Server
Type Values Removed Values Added
Metrics epss

{'score': 0.00018}

epss

{'score': 0.00052}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Metrics epss

{'score': 0.00018}

Type Values Removed Values Added
Description In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2. Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".
Title Apache HTTP Server: mod_proxy_http2 denial of service
Weaknesses CWE-617
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Nov 4, 2025, 9:11 PM
Reserved
Jun 8, 2025, 7:44 PM
Status
Modified
Published
Jul 10, 2025, 5:15 PM
Modified
Jun 17, 2026, 9:31 AM
Severity
Moderate
Public date
Jul 14, 2025, 7:22 AM