CVE-2024-52304Network attack vector

Request smuggling via unchecked chunk-extension line feeds

Published Nov 18, 2024 · Updated Nov 3, 2025

HTTP request smuggling in aiohttp before 3.10.11 allows remote attackers to bypass proxy or firewall protections via crafted chunk extensions. The pure-Python HTTP parser strips a chunk extension without first rejecting an embedded line feed, causing request boundaries to differ from stricter intermediaries. Exposure requires an installation without the C extensions or AIOHTTP_NO_EXTENSIONS enabled; a smuggled request can reach a protected application route.

CVSS severity6.3
Medium
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP request smuggling in aiohttp before 3.10.11 allows remote attackers to bypass proxy or firewall protections via crafted chunk extensions. The pure-Python HTTP parser strips a chunk extension without first rejecting an embedded line feed, causing request boundaries to differ from stricter intermediaries. Exposure requires an installation without the C extensions or AIOHTTP_NO_EXTENSIONS enabled; a smuggled request can reach a protected application route.

The record

CVE
CVE-2024-52304
Published
Nov 18, 2024
Updated
Nov 3, 2025
Vendor
aio-libs
Product
aiohttp
Classifications
CWE-444, CAPEC-33, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 18, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.10.11
  2. Affected versionversion=< 3.10.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

aio-libs · aiohttpversion=0 <3.10.11; version=< 3.10.11

Published CVSS scores

7.5NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
6.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CAPEC-33HTTP Request Smuggling
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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