---
id: "CVE-2026-121737"
page: "https://infrastack.ai/live/CVE-2026-121737"
kind: "vulnerability"
aliases: ["CVE-2026-121737"]
title: "Proxygen: pipelined HTTP/1.1 request triggers use-after-free and server crash"
severity: "high"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: [{"name": "proxygen", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["c++", "http-server", "proxygen", "runtime", "self-hosted"]
not_affected_if: ["not-using-proxygen"]
published_at: "2026-11-11T17:17:17+00:00"
first_seen_at: "2026-11-11T17:28:21+00:00"
updated_at: "2026-11-11T17:29:01+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121737", "first_seen_at": "2026-11-11T17:28:21+00:00"}]
exploit_sources: []
---

# Proxygen: pipelined HTTP/1.1 request triggers use-after-free and server crash

Link for people: https://infrastack.ai/live/CVE-2026-121737 (this .md is for agents)

A remote, unauthenticated HTTP/1.1 client can pipeline a second request and stop reading, causing proxygen's session to free that stream and then use it. This can crash the server and may allow memory corruption with further impact.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:proxygen affected range not listed fixed no fixed version listed

## How to check

- Check the proxygen version in use; affected versions are those prior to `v2026.11.09.00`.
- Look for proxygen in your server or proxy dependencies (for example a C++ build or lockfile).

## Fix

- proxygen: upgrade to `v2026.11.09.00` or later

## Timeline

- 2026-11-11T17:28:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121737

## Documents

- [fix] Patch: github.com https://github.com/meta/proxygen/commit/daf245bba7fe1304b9491403fe56f91153299781

## From the sources

When a remote, unauthenticated HTTP/1.1 client pipelined the start of a second request and then stopped reading, proxygen's coroutine-based HTTP session could free that pipelined stream while resetting the connection's streams on the resulting write timeout, then go on to use it. This can crash the server, leading to denial of service, and may allow memory corruption with further impact. This issue affects proxygen versions prior to v2026.11.09.00.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_