Skip to main content

Http Server EUVDEUVD-2025-21017

| CVE-2025-49630 HIGH
Reachable Assertion (CWE-617)
2025-07-10 security@apache.org
Apache Denial Of Service Http Server Red Hat Suse Apache HTTP Server
7.5
CVSS 3.1 · NVD
Share

Severity by source

NVD PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Ubuntu
MEDIUM
qualitative
SUSE
HIGH
qualitative
Red Hat
7.5 MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

4
Patch released
Mar 31, 2026 - 21:13 nvd
Patch available
EUVD ID Assigned
Mar 16, 2026 - 06:52 euvd
EUVD-2025-21017
Analysis Generated
Mar 16, 2026 - 06:52 vuln.today
CVE Published
Jul 10, 2025 - 17:15 nvd
HIGH 7.5

DescriptionCVE.org

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".

AnalysisAI

CVE-2025-49630 is a denial of service vulnerability in Apache HTTP Server versions 2.4.26 through 2.4.63 that can be triggered by untrusted remote clients when a reverse proxy is configured with HTTP/2 backend support and ProxyPreserveHost enabled, causing an assertion failure that crashes the proxy process. The vulnerability has a CVSS score of 7.5 (High) with network-accessible attack vector and no authentication required, making it immediately exploitable by unauthenticated remote attackers.

Technical ContextAI

This vulnerability resides in mod_proxy_http2, the Apache HTTP Server module responsible for proxying HTTP/2 connections to backend servers. The root cause is classified as CWE-617 (Reachable Assertion), indicating that an assertion statement in the code can be triggered by attacker-controlled input, leading to abnormal termination. The vulnerability is specifically triggered in reverse proxy configurations where ProxyPreserveHost is set to 'on', which causes the proxy to forward the original client's Host header to the backend HTTP/2 server. The affected CPE scope includes Apache HTTP Server versions 2.4.26 through 2.4.63, encompassing approximately 38 minor versions across a 7+ year release timeline. The HTTP/2 protocol implementation in mod_proxy_http2 fails to properly validate or handle certain client-supplied requests when combined with host header preservation, resulting in a code path that triggers an unguarded assertion.

RemediationAI

patch: Upgrade Apache HTTP Server to version 2.4.64 or later, which contains the fix for the mod_proxy_http2 assertion handling; affected_versions_fixed: 2.4.64+ (Apache) workaround: If immediate patching is not feasible, disable ProxyPreserveHost by setting 'ProxyPreserveHost off' in the reverse proxy configuration, or remove HTTP/2 backend proxy rules and fall back to HTTP/1.1 for backend connections; configuration_change: ProxyPreserveHost off; risk_note: Workaround alters proxy behavior; client Host headers will not be preserved to backend, potentially breaking hostname-dependent backend services mitigation: Implement network-level access controls to restrict which clients can reach the reverse proxy, reducing attack surface while patches are deployed; deployment: WAF, firewall rules, or reverse proxy authentication monitoring: Monitor Apache error logs and process crash reports for assertion failures in mod_proxy_http2; implement alerting on unexpected httpd process restarts

More in Http Server

View all
CVE-2017-9798 HIGH POC
7.5 Sep 18

Apache httpd allows remote attackers to read secret data from process memory if the Limit directive can be set in a user
CVE-2013-2566 MEDIUM POC
5.9 Mar 15

The RC4 algorithm, as used in the TLS protocol and SSL protocol, has many single-byte biases, which makes it easier for

CVE-2014-0226 MEDIUM POC
6.8 Jul 20

Race condition in the mod_status module in the Apache HTTP Server before 2.4.10 allows remote attackers to cause a denia
CVE-2016-8740 HIGH POC
7.5 Dec 05

The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2
CVE-2013-5704 MEDIUM POC
5.0 Apr 15

The mod_headers module in the Apache HTTP Server 2.2.22 allows remote attackers to bypass "RequestHeader unset" directiv
CVE-2013-2249 HIGH POC
7.5 Jul 23

mod_session_dbd.c in the mod_session_dbd module in the Apache HTTP Server before 2.4.5 proceeds with save operations for
CVE-2016-5387 HIGH
8.1 Jul 19

The Apache HTTP Server through 2.4.23 follows RFC 3875 section 4.1.18 and therefore does not protect applications from t
CVE-2017-7668 HIGH
7.5 Jun 20

The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token list parsing, which al
CVE-2017-3169 CRITICAL POC
9.8 Jun 20

In Apache httpd 2.2.x before 2.2.33 and 2.4.x before 2.4.26, mod_ssl may dereference a NULL pointer when third-party mod
CVE-2016-0736 HIGH POC
7.5 Jul 27

In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto was encrypting its data/cookie using the configured c
CVE-2017-7679 CRITICAL POC
9.8 Jun 20

In Apache httpd 2.2.x before 2.2.33 and 2.4.x before 2.4.26, mod_mime can read one byte past the end of a buffer when se
CVE-2012-0053 MEDIUM POC
4.3 Jan 28

protocol.c in the Apache HTTP Server 2.2.x through 2.2.21 does not properly restrict header information during construct

Same weakness CWE-617 – Reachable Assertion

View all
CVE-2016-8864 HIGH
7.5
CVE-2020-12417 HIGH POC
8.8
CVE-2020-6623 HIGH POC
8.8
CVE-2020-6619 HIGH POC
8.8
CVE-2020-6617 HIGH POC
8.8
CVE-2023-37023 HIGH POC
8.6
CVE-2023-37021 HIGH POC
8.6
CVE-2023-37020 HIGH POC
8.6

Same technique Denial Of Service

View all
CVE-2015-5119 CRITICAL POC
9.8
CVE-2011-2462 CRITICAL POC
9.8
CVE-2011-0611 HIGH POC
8.8
CVE-2012-1889 HIGH POC
8.8
CVE-2012-0507 CRITICAL POC
9.8
CVE-2014-1761 HIGH POC
7.8
CVE-2015-5122 CRITICAL POC
9.8
CVE-2011-0609 HIGH POC
7.8

Vendor StatusVendor

Ubuntu

Priority: Medium
apache2
Release Status Version
upstream released 2.4.64-1
trusty not-affected -
xenial not-affected -
bionic released 2.4.29-1ubuntu4.27+esm6
focal released 2.4.41-4ubuntu3.23+esm2
jammy released 2.4.52-1ubuntu4.15
noble released 2.4.58-1ubuntu8.7
plucky released 2.4.63-1ubuntu1.1
USN-7639-1 USN-7639-2

Debian

apache2
Release Status Fixed Version Urgency
bullseye fixed 2.4.65-1~deb11u1 -
bullseye (security) fixed 2.4.66-1~deb11u1 -
bookworm fixed 2.4.65-1~deb12u1 -
bookworm (security) vulnerable 2.4.62-1~deb12u2 -
trixie fixed 2.4.66-1~deb13u2 -
forky, sid fixed 2.4.66-8 -
(unstable) fixed 2.4.64-1 -
DLA-4270-1

SUSE

Severity: High
Product Status
Container suse/manager/4.3/proxy-httpd:4.3.16.9.67.10 Image SLES15-SP4-Manager-Proxy-4-3-BYOS Image SLES15-SP4-Manager-Proxy-4-3-BYOS-Azure Image SLES15-SP4-Manager-Proxy-4-3-BYOS-EC2 Image SLES15-SP4-Manager-Proxy-4-3-BYOS-GCE Image SLES15-SP4-Manager-Server-4-3-BYOS Image SLES15-SP4-Manager-Server-4-3-BYOS-Azure Image SLES15-SP4-Manager-Server-4-3-BYOS-EC2 Image SLES15-SP4-Manager-Server-4-3-BYOS-GCE Image SLES15-SP4-SAP Image SLES15-SP4-SAP-Azure Image SLES15-SP4-SAP-EC2 Image SLES15-SP4-SAP-GCE Image SLES15-SP4-SAPCAL Image SLES15-SP4-SAPCAL-Azure Image SLES15-SP4-SAPCAL-EC2 Image SLES15-SP4-SAPCAL-GCE Image SLES15-SP5-SAPCAL-Azure Image SLES15-SP5-SAPCAL-EC2 Image SLES15-SP5-SAPCAL-GCE Affected
Container suse/manager/5.0/x86_64/proxy-httpd:5.0.5.1.7.26.2 Container suse/manager/5.0/x86_64/server:5.0.5.1.7.33.2 Image SLES15-SP6-SAP Image SLES15-SP6-SAP-Azure Image SLES15-SP6-SAP-EC2 Image SLES15-SP6-SAP-GCE Image SLES15-SP6-SAPCAL Image SLES15-SP6-SAPCAL-Azure Image SLES15-SP6-SAPCAL-EC2 Image SLES15-SP6-SAPCAL-GCE Affected
Container suse/multi-linux-manager/5.1/x86_64/proxy-httpd:5.1.1.8.9.2 Container suse/multi-linux-manager/5.1/x86_64/proxy-salt-broker:5.1.2.9.13.2 Container suse/multi-linux-manager/5.1/x86_64/server:5.1.1.8.7.1 Image SLES15-SP7-SAPCAL-Azure Image SLES15-SP7-SAPCAL-EC2 Image SLES15-SP7-SAPCAL-GCE Image proxy-httpd-image Image server-image Affected
SUSE Enterprise Storage 7.1 Fixed
SUSE Liberty Linux 8 Fixed

Share

EUVD-2025-21017 vulnerability details – vuln.today
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy