# CVE-2026-34441: cpp-httplib: HTTP Request Smuggling via Unconsumed GET Request Body

> Attackers can smuggle arbitrary HTTP requests via unconsumed GET bodies in cpp-httplib, potentially bypassing security controls or executing code.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Mar 2026
- **Updated:** 1 Apr 2026
- **Also known as:** DEBIAN-CVE-2026-34441, GHSA-jv63-rm9j-6jwc, UBUNTU-CVE-2026-34441

## What is CVE-2026-34441?

CVE-2026-34441 is a medium-severity vulnerability in yhirose cpp-httplib, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.40.0, cpp-httplib is vulnerable to HTTP Request Smuggling. The server's static file handler serves GET responses without consuming the request body. On HTTP/1.1 keep-alive connections, the unread body bytes remain on the TCP stream and are interpreted as the start of a new HTTP request. An attacker can embed an arbitrary HTTP request inside the body of a GET request, which the server processes as a separate request. This issue has been patched in version 0.40.0.

Weakness: CWE-444 (Inconsistent Interpretation of HTTP Requests)

## Which versions are affected by CVE-2026-34441?

It affects 1 product.


Products: Yhirose Cpp-Httplib.

## How do I fix CVE-2026-34441?

Upgrade to a fixed version.

## Is CVE-2026-34441 being exploited?

There is no known exploitation of CVE-2026-34441 in the wild and no public exploit code.

## Other vulnerabilities in yhirose cpp-httplib

- [CVE-2025-66570](https://insights.sbomify.com/CVE-2025-66570/): cpp-httplib Untrusted HTTP Header Handling: Internal Header Shadowing (REMOTE*/LOCAL*) (critical 10.0)
- [CVE-2026-45372](https://insights.sbomify.com/CVE-2026-45372/): cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection (critical 9.9)
- [CVE-2026-46527](https://insights.sbomify.com/CVE-2026-46527/): Null dereference in cpp-httplib (high 8.7)
- [CVE-2026-32627](https://insights.sbomify.com/CVE-2026-32627/): cpp-httplib has a Silent TLS Certificate Verification Bypass on HTTPS Redirect via Proxy (high 8.7)
- [CVE-2026-22776](https://insights.sbomify.com/CVE-2026-22776/): cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34441 and fix it if it is affected.

What it is: CVE-2026-34441 is a medium-severity vulnerability in yhirose cpp-httplib, published on 31 Mar 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-2026-34441 in the wild and no public exploit code.

Affected product: yhirose cpp-httplib. 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-2026-34441/ (Markdown: https://insights.sbomify.com/CVE-2026-34441/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34441
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34441
- OSV: https://osv.dev/vulnerability/CVE-2026-34441

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-34441/
Summaries are generated and may contain mistakes; the official description above is the record.