CVE-2023-47641Public exploitNetwork attack vector

Proxy rule bypass via conflicting message framing

Published Nov 14, 2023 · Updated Nov 3, 2025

HTTP request smuggling in aiohttp before 3.8.0 allows remote attackers to bypass proxy rules through conflicting message framing. The HTTP parser treats any Transfer-Encoding value containing chunked as chunked, while affected releases fail to reject a simultaneous Content-Length header. Exploitation requires a reverse proxy that honors Content-Length while aiohttp honors Transfer-Encoding, enabling persistent-socket poisoning and cross-user header exposure.

CVSS severity6.5
Medium
EPSS probability0.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

HTTP request smuggling in aiohttp before 3.8.0 allows remote attackers to bypass proxy rules through conflicting message framing. The HTTP parser treats any Transfer-Encoding value containing chunked as chunked, while affected releases fail to reject a simultaneous Content-Length header. Exploitation requires a reverse proxy that honors Content-Length while aiohttp honors Transfer-Encoding, enabling persistent-socket poisoning and cross-user header exposure.

The record

CVE
CVE-2023-47641
Published
Nov 14, 2023
Updated
Nov 3, 2025
Vendor
aio-libs
Product
aiohttp
Classifications
CWE-444, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 14, 2023CVE 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 3.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

aio-libs · aiohttpversion=< 3.8.0

Published CVSS scores

6.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
3.4GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N

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 exploitPublished

Weakness, pattern, technique

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

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo