CVE-2026-49975 Apache HTTP Server: mod_http2 denial of service
High 7.5
Published
Updated
Check this codebase for CVE-2026-49975 and fix it if it is affected.
What it is: CVE-2026-49975 is a high-severity denial of service vulnerability in Apache Http Server, published on 8 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49975 exists.
Affected packages and fixed versions:
- apache (Bitnami): affected from 2.4.17; fixed in 2.4.68
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-49975/ (Markdown: https://insights.sbomify.com/CVE-2026-49975/index.md)
Attackers can cause denial of service in Apache HTTP Server by sending malicious HTTP requests that trigger excessive memory allocation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-49975?
CVE-2026-49975 is a high-severity denial of service vulnerability in Apache Http Server, published on 8 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests.
This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.
Which versions are affected by CVE-2026-49975?
1 open source package ship an affected version, including apache. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
apache Bitnami | From 2.4.17 | 2.4.68 |
Linux distribution packages (39)
mod_http2 AlmaLinux:10 | All versions | 2.0.29-4.el10_2.1 |
httpd AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
httpd AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
httpd-devel AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
httpd-devel AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
httpd-filesystem AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
httpd-manual AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
httpd-tools AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
httpd-tools AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
mod_http2 AlmaLinux:8 | All versions | 1.15.7-10.module_el8.10.0+4190+704ad79b.6 |
mod_ldap AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
mod_ldap AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
mod_md AlmaLinux:8 | All versions | 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2 |
mod_proxy_html AlmaLinux:8 | All versions | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
mod_proxy_html AlmaLinux:8 | All versions | 1:2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
mod_session AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
mod_session AlmaLinux:8 | All versions | 2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
mod_ssl AlmaLinux:8 | All versions | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 |
mod_ssl AlmaLinux:8 | All versions | 1:2.4.37-65.module_el8.10.0+4190+704ad79b.8 |
mod_http2 AlmaLinux:9 | All versions | 2.0.26-6.el9_8.1 |
mod_http2 Red Hat:enterprise_linux:10.2 | All versions | 0:2.0.29-4.el10_2.1 |
mod_http2-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 0:2.0.29-4.el10_2.1 |
mod_http2-debugsource Red Hat:enterprise_linux:10.2 | All versions | 0:2.0.29-4.el10_2.1 |
httpd Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
httpd-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
httpd-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
httpd-devel Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
httpd-filesystem Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
httpd-manual Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
httpd-tools Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
httpd-tools-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
mod_http2 Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.7-10.module+el8.10.0+24368+ad388a0c.6 |
mod_http2-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.7-10.module+el8.10.0+24368+ad388a0c.6 |
mod_http2-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 0:1.15.7-10.module+el8.10.0+24368+ad388a0c.6 |
mod_ldap Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
mod_ldap-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.37-65.module+el8.10.0+24281+ea10630c.8 |
mod_md Red Hat:enterprise_linux:8::appstream | All versions | 1:2.0.8-8.module+el8.10.0+23815+1b5e1c66.2 |
mod_md-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 1:2.0.8-8.module+el8.10.0+23815+1b5e1c66.2 |
mod_md-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 1:2.0.8-8.module+el8.10.0+23815+1b5e1c66.2 |
Products include Apache Http Server, Debian Debian Linux.
How do I fix CVE-2026-49975?
Upgrade apache to 2.4.68 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-2026-49975 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49975 exists.
Public exploit code: 14 proofs of concept on GitHub.
Other vulnerabilities in Apache Http Server
Sources
Also known as ALPINE-CVE-2026-49975, ALSA-2026:25057, ALSA-2026:25090, ALSA-2026:25225, AZL-89510, AZL-89550 and 47 more.