CVE-2026-58055 nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length
Medium 6.3
Published
Updated
Check this codebase for CVE-2026-58055 and fix it if it is affected.
What it is: CVE-2026-58055 is a medium-severity vulnerability in nghttp2, published on 28 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-58055 in the wild and no public exploit code.
Affected product: nghttp2. No package-level version data is available, so check the vendor advisory linked from the reference page.
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-2026-58055/ (Markdown: https://insights.sbomify.com/CVE-2026-58055/index.md)
Attackers can exploit HTTP request smuggling in nghttpx proxy to poison response queues and access or modify data across clients.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-58055?
CVE-2026-58055 is a medium-severity vulnerability in nghttp2, published on 28 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting ambiguous message in the attacker's favor enables HTTP request/response smuggling and cross-client response-queue poisoning.
Weakness: CWE-444
Which versions are affected by CVE-2026-58055?
It affects 1 product.
Linux distribution packages (40)
libnghttp2 AlmaLinux:10 | All versions | 1.68.0-3.el10_2.2 |
libnghttp2-devel AlmaLinux:10 | All versions | 1.68.0-3.el10_2.2 |
nghttp2 AlmaLinux:10 | All versions | 1.68.0-3.el10_2.2 |
libnghttp2 AlmaLinux:8 | All versions | 1.33.0-6.el8_10.3 |
libnghttp2-devel AlmaLinux:8 | All versions | 1.33.0-6.el8_10.3 |
nghttp2 AlmaLinux:8 | All versions | 1.33.0-6.el8_10.3 |
libnghttp2 AlmaLinux:9 | All versions | 1.43.0-6.el9_8.2 |
libnghttp2-devel AlmaLinux:9 | All versions | 1.43.0-6.el9_8.2 |
nghttp2 AlmaLinux:9 | All versions | 1.43.0-6.el9_8.2 |
libnghttp2 Red Hat:enterprise_linux:10.2 | All versions | 0:1.68.0-3.el10_2.2 |
libnghttp2-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 0:1.68.0-3.el10_2.2 |
libnghttp2-devel Red Hat:enterprise_linux:10.2 | All versions | 0:1.68.0-3.el10_2.2 |
nghttp2 Red Hat:enterprise_linux:10.2 | All versions | 0:1.68.0-3.el10_2.2 |
nghttp2-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 0:1.68.0-3.el10_2.2 |
nghttp2-debugsource Red Hat:enterprise_linux:10.2 | All versions | 0:1.68.0-3.el10_2.2 |
libnghttp2 Red Hat:enterprise_linux:8::baseos | All versions | 0:1.33.0-6.el8_10.3 |
libnghttp2-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:1.33.0-6.el8_10.3 |
nghttp2 Red Hat:enterprise_linux:8::baseos | All versions | 0:1.33.0-6.el8_10.3 |
nghttp2-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:1.33.0-6.el8_10.3 |
nghttp2-debugsource Red Hat:enterprise_linux:8::baseos | All versions | 0:1.33.0-6.el8_10.3 |
libnghttp2-debuginfo Red Hat:enterprise_linux:8::crb | All versions | 0:1.33.0-6.el8_10.3 |
libnghttp2-devel Red Hat:enterprise_linux:8::crb | All versions | 0:1.33.0-6.el8_10.3 |
nghttp2 Red Hat:enterprise_linux:8::crb | All versions | 0:1.33.0-6.el8_10.3 |
nghttp2-debuginfo Red Hat:enterprise_linux:8::crb | All versions | 0:1.33.0-6.el8_10.3 |
nghttp2-debugsource Red Hat:enterprise_linux:8::crb | All versions | 0:1.33.0-6.el8_10.3 |
libnghttp2 Red Hat:enterprise_linux:9::baseos | All versions | 0:1.43.0-6.el9_8.2 |
libnghttp2-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.43.0-6.el9_8.2 |
nghttp2 Red Hat:enterprise_linux:9::baseos | All versions | 0:1.43.0-6.el9_8.2 |
nghttp2-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.43.0-6.el9_8.2 |
nghttp2-debugsource Red Hat:enterprise_linux:9::baseos | All versions | 0:1.43.0-6.el9_8.2 |
libnghttp2-debuginfo Red Hat:enterprise_linux:9::crb | All versions | 0:1.43.0-6.el9_8.2 |
libnghttp2-devel Red Hat:enterprise_linux:9::crb | All versions | 0:1.43.0-6.el9_8.2 |
nghttp2 Red Hat:enterprise_linux:9::crb | All versions | 0:1.43.0-6.el9_8.2 |
nghttp2-debuginfo Red Hat:enterprise_linux:9::crb | All versions | 0:1.43.0-6.el9_8.2 |
nghttp2-debugsource Red Hat:enterprise_linux:9::crb | All versions | 0:1.43.0-6.el9_8.2 |
libnghttp2 Red Hat:hummingbird:1 | All versions | 0:1.69.0-3.1.hum1 |
libnghttp2 Red Hat:hummingbird:1 | All versions | 0:1.69.0-5.hum1 |
libnghttp2-devel Red Hat:hummingbird:1 | All versions | 0:1.69.0-3.1.hum1 |
libnghttp2-devel Red Hat:hummingbird:1 | All versions | 0:1.69.0-5.hum1 |
mingw32-libnghttp2 Red Hat:hummingbird:1 | All versions | 0:1.69.0-3.1.hum1 |
Products include Nghttp2 Nghttp2.
How do I fix CVE-2026-58055?
Apply the vendor's patch.
Is CVE-2026-58055 being exploited?
There is no known exploitation of CVE-2026-58055 in the wild and no public exploit code.
Other vulnerabilities in nghttp2
Sources
Also known as ALPINE-CVE-2026-58055, ALSA-2026:54650, ALSA-2026:54662, ALSA-2026:55804, AZL-91451, BELL-CVE-2026-58055 and 34 more.