GHSA-xx9p-xxvh-7g8j CVE-2023-47641 PYSEC-2023-247
Aiohttp has inconsistent interpretation of `Content-Length` vs. `Transfer-Encoding` differing in C and Python fallbacks
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.83%
- Chance of exploitation in the next 30 days. Higher than 57.67% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
- Fix
3.8.0- Upgrade aiohttp to this version or later
Description
Impact
Aiohttp has a security vulnerability regarding the inconsistent interpretation of the http protocol. As we know that HTTP/1.1 is persistent, if we have both Content-Length(CL) and Transfer-Encoding(TE) it can lead to incorrect interpretation of two entities that parse the HTTP and we can poison other sockets with this incorrect interpretation.
A possible Proof-of-Concept (POC) would be a configuration with a reverse proxy(frontend) that accepts both CL and TE headers and aiohttp as backend. As aiohttp parses anything with chunked, we can pass a chunked123 as TE, the frontend entity will ignore this header and will parse Content-Length. I can give a Dockerfile with the configuration if you want.
The impact of this vulnerability is that it is possible to bypass any proxy rule, poisoning sockets to other users like passing Authentication Headers, also if it is present an Open Redirect (just like CVE-2021-21330) we can combine it to redirect random users to our website and log the request.
References
Affected versions
PyPI
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
aiohttp PyPI → 3.8.0
- pip
pip install --upgrade "aiohttp>=3.8.0"- poetry
poetry add "aiohttp>=3.8.0"- uv
uv add "aiohttp>=3.8.0"
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- Passive
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- Low
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 3.4
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
How to prevent it
- Implementation: Use a web server that employs a strict HTTP parsing procedure, such as Apache [REF-433].
- Implementation: Use only SSL communication.
- Implementation: Terminate the client session after each request.
- System Configuration: Turn all pages to non-cacheable.
References
Advisories
Packages
Other links
- github.com/aio-libs/aiohttp/security/advisories/GHSA-xx9p-xxvh-7g8j
- github.com/aio-libs/aiohttp/commit/f016f0680e4ace6742b03a70cb0382ce86abe371
- github.com/aio-libs/aiohttp/releases/tag/v3.8.0
- github.com/pypa/advisory-database/tree/main/vulns/aiohttp/PYSEC-2023-247.yaml
- lists.debian.org/debian-lts-announce/2025/02/msg00002.html
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-pqxq-w44r-73xw AIOHTTP: Pure-Python parser request smuggling | Medium | Also affects aiohttp |
| GHSA-gx76-c99x-2c96 AIOHTTP: Cookie from subdomain can remove Host-Only Scope from existing cookies | Low | Also affects aiohttp |
| GHSA-f9xw-jh8m-3mwq AIOHTTP: Absolute-form request targets can spoof Request.scheme | Medium | Also affects aiohttp |
| GHSA-9xw5-w5jj-pvcg AIOHTTP: File descriptor exhaustion in multipart requests | High | Also affects aiohttp |
| GHSA-6cjc-53gc-5rqm AIOHTTP: Connector pool exhaustion via Max-Age overflow | Medium | Also affects aiohttp |
| GHSA-5wr8-gcqf-gqf3 aiohttp server lacks an initial request/header timeout | High | Also affects aiohttp |
| GHSA-494j-54xm-rwp3 AIOHTTP: Secure attribute not enforced for shared cookie | Medium | Also affects aiohttp |
| GHSA-2g87-pp6c-29x5 aiohttp: Multiple instances of excessive or unbounded memory/CPU use | High | Also affects aiohttp |
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