// For flags

CVE-2025-49630

Apache HTTP Server: mod_proxy_http2 denial of service

Severity Score

7.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Attend
*SSVC
Descriptions

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".

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".

It was discovered that the Apache HTTP Server incorrectly handled certain Content-Type response headers. A remote attacker could possibly use this issue to perform HTTP response splitting attacks. xiaojunjie discovered that the Apache HTTP Server mod_proxy module incorrectly handled certain requests. A remote attacker could possibly use this issue to send outbound proxy requests to an arbitrary URL.

*Credits: Anthony CORSIEZ
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial
* Common Vulnerability Scoring System
SSVC
  • Decision:Attend
Exploitation
None
Automatable
Yes
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2025-06-08 CVE Reserved
  • 2025-07-10 CVE Published
  • 2025-07-15 CVE Updated
  • 2025-07-16 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-617: Reachable Assertion
CAPEC
References (1)
URL Tag Source
URL Date SRC
URL Date SRC
URL Date SRC
https://httpd.apache.org/security/vulnerabilities_24.html 2025-07-10
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Apache Software Foundation
Search vendor "Apache Software Foundation"
 Apache HTTP Server
Search vendor "Apache Software Foundation" for product "Apache HTTP Server"
 >= 2.4.26 <= 2.4.63
Search vendor "Apache Software Foundation" for product "Apache HTTP Server" and version " >= 2.4.26 <= 2.4.63"
en
Affected