---
id: CVE-2026-22815
aliases:
  - GHSA-w2fm-2cpv-w7v5
  - PYSEC-2026-2094
title: >-
  aiohttp allows unlimited trailer headers, leading to possible uncapped memory
  usage
summary: >-
  aiohttp allows unlimited trailer headers, leading to possible uncapped memory
  usage
severity: medium
vendor: aiohttp
product: aiohttp
ecosystem: pip
affected:
  - aiohttp < 3.13.4
patched:
  - aiohttp 3.13.4
published: '2026-04-01'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:51:03.588955358Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-w2fm-2cpv-w7v5'
references:
  - url: >-
      https://github.com/aio-libs/aiohttp/security/advisories/GHSA-w2fm-2cpv-w7v5
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-22815'
  - url: >-
      https://github.com/aio-libs/aiohttp/commit/0c2e9da51126238a421568eb7c5b53e5b5d17b36
  - url: 'https://github.com/aio-libs/aiohttp'
  - url: 'https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4'
tags:
  - osv
  - pip
epss: 0.0044
epssPercentile: 0.35638
ingestedAt: '2026-07-13T18:58:03.978Z'
---

## Overview

### Summary

Insufficient restrictions in header/trailer handling could cause uncapped memory usage.

### Impact

An application could cause memory exhaustion when receiving an attacker controlled request or response. A vulnerable web application could mitigate these risks with a typical reverse proxy configuration.

-----

Patch: https://github.com/aio-libs/aiohttp/commit/0c2e9da51126238a421568eb7c5b53e5b5d17b36

## Affected packages

- `aiohttp < 3.13.4`

## Remediation

Upgrade to a patched release:

- `aiohttp 3.13.4`