CVE-2025-49630 Apache HTTP Server: mod_proxy_http2 denial of service
Untrusted clients can cause a denial of service in Apache HTTP Server when using a specific reverse proxy configuration with HTTP/2 backends.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-49630?
CVE-2025-49630 is a high-severity denial of service vulnerability in Apache Http Server, published on 10 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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".
Weakness: CWE-617
Which versions are affected by CVE-2025-49630?
1 open source package ship an affected version, including apache. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
apache Bitnami | From 2.4.26 | 2.4.64 |
Linux distribution packages (19)
mod_http2 AlmaLinux:10 | All versions | 2.0.29-2.el10_0.1 |
mod_http2 AlmaLinux:9 | All versions | 2.0.26-4.el9_6.1 |
mod_http2 Red Hat:enterprise_linux:10.0 | All versions | 0:2.0.29-2.el10_0.1 |
mod_http2-debuginfo Red Hat:enterprise_linux:10.0 | All versions | 0:2.0.29-2.el10_0.1 |
mod_http2-debugsource Red Hat:enterprise_linux:10.0 | All versions | 0:2.0.29-2.el10_0.1 |
mod_http2 Red Hat:enterprise_linux:9::appstream | All versions | 0:2.0.26-4.el9_6.1 |
mod_http2-debuginfo Red Hat:enterprise_linux:9::appstream | All versions | 0:2.0.26-4.el9_6.1 |
mod_http2-debugsource Red Hat:enterprise_linux:9::appstream | All versions | 0:2.0.26-4.el9_6.1 |
mod_http2 Red Hat:rhel_e4s:9.0::appstream | All versions | 0:1.15.19-3.el9_0.7 |
mod_http2-debuginfo Red Hat:rhel_e4s:9.0::appstream | All versions | 0:1.15.19-3.el9_0.7 |
mod_http2-debugsource Red Hat:rhel_e4s:9.0::appstream | All versions | 0:1.15.19-3.el9_0.7 |
mod_http2 Red Hat:rhel_e4s:9.2::appstream | All versions | 0:1.15.19-4.el9_2.7 |
mod_http2-debuginfo Red Hat:rhel_e4s:9.2::appstream | All versions | 0:1.15.19-4.el9_2.7 |
mod_http2-debugsource Red Hat:rhel_e4s:9.2::appstream | All versions | 0:1.15.19-4.el9_2.7 |
mod_http2 Red Hat:rhel_eus:9.4::appstream | All versions | 0:2.0.26-2.el9_4.2 |
mod_http2-debuginfo Red Hat:rhel_eus:9.4::appstream | All versions | 0:2.0.26-2.el9_4.2 |
mod_http2-debugsource Red Hat:rhel_eus:9.4::appstream | All versions | 0:2.0.26-2.el9_4.2 |
mod_http2 Rocky Linux:10 | All versions | 0:2.0.29-2.el10_0.1 |
mod_http2 Rocky Linux:9 | All versions | 0:2.0.26-4.el9_6.1 |
Products include Apache Http Server.
How do I fix CVE-2025-49630?
Upgrade apache to 2.4.64 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-49630 being exploited?
There is no known exploitation of CVE-2025-49630 in the wild and no public exploit code.
Other vulnerabilities in Apache Http Server
Sources
Also known as ALPINE-CVE-2025-49630, ALSA-2025:14625, ALSA-2025:14983, AZL-65133, AZL-65142, AZL-65175 and 18 more.