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AIOHTTP's HTTP Parser auto_decompress feature is vulnerable to zip bomb

High severity GitHub Reviewed Published Jan 5, 2026 in aio-libs/aiohttp • Updated Jan 6, 2026

Package

pip aiohttp (pip)

Affected versions

<= 3.13.2

Patched versions

3.13.3

Description

Summary

A zip bomb can be used to execute a DoS against the aiohttp server.

Impact

An attacker may be able to send a compressed request that when decompressed by aiohttp could exhaust the host's memory.

Patch: aio-libs/aiohttp@2b920c3

References

@Dreamsorcerer Dreamsorcerer published to aio-libs/aiohttp Jan 5, 2026
Published by the National Vulnerability Database Jan 5, 2026
Published to the GitHub Advisory Database Jan 5, 2026
Reviewed Jan 5, 2026
Last updated Jan 6, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(46th percentile)

Weaknesses

Improper Handling of Highly Compressed Data (Data Amplification)

The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output. Learn more on MITRE.

Allocation of Resources Without Limits or Throttling

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. Learn more on MITRE.

CVE ID

CVE-2025-69223

GHSA ID

GHSA-6mq8-rvhq-8wgg

Source code

Credits

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