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CVE-2026-54277

AIOHTTP: C HTTP Parser Bypasses max_line_size for Fragmented Lines

Published: Jun 22, 2026Updated: Jun 30, 2026 Sources: CVE List NVDCWE-770
7.5HIGH
NVD MITRE
EPSS Score
0.3%
Top 75.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, it is possible to bypass the max_line_size check in parts of an HTTP request in the C parser. If using the optimised C parser (the default in pre-built wheels), then an attacker may be able to send oversized lines through the HTTP parser and use an excessive amount of memory, potentially leading to DoS. This vulnerability is fixed in 3.14.1.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-770

Affected Products

aio-libs
oss-projectaka aiohttp, aiohttp session, aiosmtpd
aiohttpLibrary
OSS Libraries / web-framework
aiohttp
oss-project
aiohttpLibrary
OSS Libraries / web-framework

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-63hw-fmq6-xxg2
github.com
https://github.com/aio-libs/aiohttp/commit/5ab61bb4cd88f19b712f12c7c9295fe262bf804d
github.com

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