CVE-2023-49081: Aiohttp Aiohttp's ClientSession Is Vulnerable To Vulnerability
MODERATECVE-2023-49081 is a MODERATE (CVSS 7.2) aiohttp's clientsession is vulnerable to vulnerability (CWE-20: Improper Input Validation) affecting Aiohttp libraries in the PyPI ecosystem. The issue involves aiohttp's clientsession is vulnerable to crlf injection via version. Remediation is available by upgrading affected packages to version 3.9.0.
CVE-2023-49081 at a Glance
Security Impact
CVSS: 7.2
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N).
How to Fix CVE-2023-49081
To remediate this vulnerability, upgrade all affected Aiohttp dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
pip install aiohttp>=3.9.0Run the following command in your project directory to verify that all resolved dependencies use the patched release:
pip show aiohttpHow to Check if You Are Affected
To determine whether your Python environment is affected by CVE-2023-49081, inspect your installed packages using pip:
pip show aiohttpAnalyze the terminal output to locate any version of Aiohttp in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.9.0), your application is affected.
Note: The pip show aiohttp command checks currently installed packages in your active Python environment.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Aiohttp, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2023-49081 Affected Aiohttp Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
aiohttp
|
PyPI |
< 3.9.0
|
3.9.0
|
References
Frequently Asked Questions
What is CVE-2023-49081?
Which Aiohttp versions are affected?
What version fixes CVE-2023-49081?
Is aiohttp affected?
What is the CVSS score of CVE-2023-49081?
What CWE is associated with CVE-2023-49081?
How can I check PyPI dependencies for CVE-2023-49081?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-q3qx-c6g2-7pw2",
"modified" : "2025-11-03T22:32:00Z",
"published" : "2023-11-27T23:17:42Z",
"aliases" : [ "CVE-2023-49081" ],
"summary" : "aiohttp's ClientSession is vulnerable to CRLF injection via version",
"details" : "### Summary\nImproper validation make it possible for an attacker to modify the HTTP request (e.g. to insert a new header) or even create a new HTTP request if the attacker controls the HTTP version.\n\n### Details\nThe vulnerability only occurs if the attacker can control the HTTP version of the request (including its type).\nFor example if an unvalidated JSON value is used as a version and the attacker is then able to pass an array as the `version` parameter.\nFurthermore, the vulnerability only occurs when the `Connection` header is passed to the `headers` parameter.\n\nAt this point, the library will use the parsed value to create the request. If a list is passed, then it bypasses validation and it is possible to perform CRLF injection.\n\n### PoC\nThe POC below shows an example of providing an unvalidated array as a version:\nhttps://gist.github.com/jnovikov/184afb593d9c2114d77f508e0ccd508e\n\n### Impact\nCRLF injection leading to Request Smuggling.\n\n### Workaround\nIf these specific conditions are met and you are unable to upgrade, then validate the user input to the `version` parameter to ensure it is a `str`.\n\nPatch: https://github.com/aio-libs/aiohttp/pull/7835/files",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N"
}, {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "PyPI",
"name" : "aiohttp"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "3.9.0"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/aio-libs/aiohttp/security/advisories/GHSA-q3qx-c6g2-7pw2"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-49081"
}, {
"type" : "WEB",
"url" : "https://github.com/aio-libs/aiohttp/pull/7835/files"
}, {
"type" : "WEB",
"url" : "https://github.com/aio-libs/aiohttp/commit/1e86b777e61cf4eefc7d92fa57fa19dcc676013b"
}, {
"type" : "WEB",
"url" : "https://gist.github.com/jnovikov/184afb593d9c2114d77f508e0ccd508e"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/aio-libs/aiohttp"
}, {
"type" : "WEB",
"url" : "https://github.com/pypa/advisory-database/tree/main/vulns/aiohttp/PYSEC-2023-250.yaml"
}, {
"type" : "WEB",
"url" : "https://lists.debian.org/debian-lts-announce/2025/02/msg00002.html"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TY5SI6NK5243DEEDQUFKQKW5GQNKQUMA"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WSYWMP64ZFCTC3VO6RY6EC6VSSMV6I3A"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-20" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2023-11-27T23:17:42Z",
"nvd_published_at" : "2023-11-30T07:15:08Z"
}
}