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Aiohttp CVE-2023-47627

HIGH
HTTP Request/Response Smuggling (CWE-444)
2023-11-14 security-advisories@github.com
7.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V4 - API and Web Service HTTP request consistency
Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A remote attacker could manipulate HTTP request interpretation between frontend and backend servers by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.9% exploitation probability (EPSS)

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AnalysisAI

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Enforce strict HTTP parsing, normalize requests at proxy layer, use HTTP/2 end-to-end, reject ambiguous headers.

Affected Packages

pypi aiohttp fix: 3.8.6

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in pypi

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as HTTP Request/Response Smuggling (CWE-444), which allows attackers to manipulate HTTP request interpretation between frontend and backend servers. aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. The HTTP parser in AIOHTTP has numerous problems with header parsing, which could lead to request smuggling. This parser is only used when AIOHTTP_NO_EXTENSIONS is enabled (or not using a prebuilt wheel). These bugs have been addressed in commit d5c12ba89 which has been included in release version 3.8.6. Users are advised to upgrade. There are no known workarounds for these issues. Affected products include: Aiohttp. Version information: version 3.8.6..

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

DescriptionNVD

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. The HTTP parser in AIOHTTP has numerous problems with header parsing, which could lead to request smuggling. This parser is only used when AIOHTTP_NO_EXTENSIONS is enabled (or not using a prebuilt wheel). These bugs have been addressed in commit d5c12ba89 which has been included in release version 3.8.6. Users are advised to upgrade. There are no known workarounds for these issues.

Threat Intelligence Overview

EPSS Score
0.9%
Top 46% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 0.9%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

59
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +38
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

HTTP request smuggling exploits inconsistencies in how front-end and back-end servers parse HTTP message boundaries.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)NVD

cpe:2.3:a:aiohttp:aiohttp:*:*:*:*:*:*:*:*
CVE-2023-37276 HIGH POC
7.5 Jul 19

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Rated high severity (CVSS 7.5), this vul

CVE-2026-69244 HIGH POC
7.1 Aug 03

Out-of-bounds heap read in aiohttp's C HTTP response parser (versions ≤ 3.14.2) allows an attacker-controlled server to

CVE-2026-59881 MEDIUM POC
6.9 Jul 30

Uncontrolled decompression in aiohttp's WebSocket client prior to version 3.14.2 allows a malicious server to exhaust CP

CVE-2023-47641 MEDIUM POC
6.5 Nov 14

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Rated medium severity (CVSS 6.5), this v

CVE-2026-69243 MEDIUM POC
6.3 Aug 03

HTTP request smuggling in aiohttp's server-side parser allows unauthenticated remote attackers to inject and misdirect H

CVE-2022-33124 MEDIUM POC
5.5 Jun 23

AIOHTTP 3.8.1 can report a "ValueError: Invalid IPv6 URL" outcome, which can lead to a Denial of Service (DoS). Rated me

CVE-2023-49082 MEDIUM POC
5.3 Nov 29

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Rated medium severity (CVSS 5.3), this v

CVE-2023-49081 MEDIUM POC
5.3 Nov 30

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Rated medium severity (CVSS 5.3), this v

CVE-2024-52303 HIGH
8.7 Nov 18

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Rated high severity (CVSS 8.7), this vul

CVE-2026-111066 HIGH
8.2 Oct 19

Unauthenticated remote attackers can exhaust file descriptors in aiohttp-based web services by sending crafted multipart

CVE-2026-111064 HIGH
8.2 Oct 19

Idle or half-open connections to aiohttp server deployments at version 3.14.3 and earlier are never timed out during the

CVE-2025-69223 HIGH
7.5 Jan 05

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Versions 3.13.2 and below allow a zip bo

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