AIOHTTP Affected by Denial of Service (DoS) via Unbounded DNS Cache in TCPConnector

Description

Summary

An unbounded DNS cache could result in excessive memory usage possibly resulting in a DoS situation.

Impact

If an application makes requests to a very large number of hosts, this could cause the DNS cache to continue growing and slowly use excessive amounts of memory.


Patch: https://github.com/aio-libs/aiohttp/commit/c4d77c3533122be353b8afca8e8675e3b4cbda98

Basic information

Type
reviewed
Severity
low
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-04-01 21:19:22 UTC
Updated
2026-04-06 16:46:47 UTC
GitHub reviewed
2026-04-01 21:19:22 UTC
NVD published
2026-04-01

EPSS Score

Score Percentile
0.05% 16.48%

CVSS Scores

Base score Version Severity Vector
2.7 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N)
No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:L)
Limited availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:U)
Unreported: no public PoC, no reported exploitation, and no known simplification tools.

Identifiers

CWEs

CWE id Name
CWE-770 Allocation of Resources Without Limits or Throttling

Credits

  • gonas0919 (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
pip aiohttp <= 3.13.3 3.13.4

References

cvelogic Threat Intelligence