# CVE-2025-55181: Denial of service in proxygen

> An attacker can cause a denial of service by sending oversized HTTP bodies, triggering an infinite loop and memory exhaustion in the Proxygen library.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Dec 2025
- **Updated:** 3 Dec 2025
- **Also known as:** GHSA-886p-82g3-p77g

## What is CVE-2025-55181?

CVE-2025-55181 is a medium-severity denial of service vulnerability in Facebook proxygen, published on 2 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Sending an HTTP request/response body with greater than 2^31 bytes triggers an infinite loop in proxygen::coro::HTTPQuicCoroSession which blocks the backing event loop and unconditionally appends data to a std::vector per-loop iteration. This issue leads to unbounded memory growth and eventually causes the process to run out of memory.

Weakness: CWE-834 (Excessive Iteration)

## Which versions are affected by CVE-2025-55181?

It affects 1 product.


Products: Facebook Proxygen.

## How do I fix CVE-2025-55181?

No fix has been published for CVE-2025-55181 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-55181 being exploited?

There is no known exploitation of CVE-2025-55181 in the wild and no public exploit code.

## Other vulnerabilities in Facebook proxygen

- [CVE-2020-1897](https://insights.sbomify.com/CVE-2020-1897/): Use after free in proxygen (critical 9.8)
- [CVE-2019-11940](https://insights.sbomify.com/CVE-2019-11940/): Use after free in Proxygen (critical 9.8)
- [CVE-2019-11921](https://insights.sbomify.com/CVE-2019-11921/): Memory corruption in Proxygen (critical 9.8)
- [CVE-2018-6343](https://insights.sbomify.com/CVE-2018-6343/): Proxygen fails to validate that a secondary auth manager is set before dereferencing it. (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-55181 and fix it if it is affected.

What it is: CVE-2025-55181 is a medium-severity denial of service vulnerability in Facebook proxygen, published on 2 Dec 2025. 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-2025-55181 in the wild and no public exploit code.

Affected product: Facebook proxygen. 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-2025-55181/ (Markdown: https://insights.sbomify.com/CVE-2025-55181/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-55181
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-55181
- OSV: https://osv.dev/vulnerability/CVE-2025-55181

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-55181/
Summaries are generated and may contain mistakes; the official description above is the record.