GHSA-8qpw-xqxj-h4r2 CVE-2024-23829 PYSEC-2024-26
aiohttp's HTTP parser (the python one, not llhttp) still overly lenient about separators
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 1.03%
- Chance of exploitation in the next 30 days. Higher than 63.69% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
- Fix
3.9.2- Upgrade aiohttp to this version or later
Description
Summary
Security-sensitive parts of the Python HTTP parser retained minor differences in allowable character sets, that must trigger error handling to robustly match frame boundaries of proxies in order to protect against injection of additional requests. Additionally, validation could trigger exceptions that were not handled consistently with processing of other malformed input.
Details
These problems are rooted in pattern matching protocol elements, previously improved by PR #3235 and GHSA-gfw2-4jvh-wgfg:
-
The expression
HTTP/(\d).(\d)lacked another backslash to clarify that the separator should be a literal dot, not just any Unicode code point (result:HTTP/(\d)\.(\d)). -
The HTTP version was permitting Unicode digits, where only ASCII digits are standards-compliant.
-
Distinct regular expressions for validating HTTP Method and Header field names were used - though both should (at least) apply the common restrictions of rfc9110
token.
PoC
GET / HTTP/1ö1
GET / HTTP/1.𝟙
GET/: HTTP/1.1
Content-Encoding?: chunked
Impact
Primarily concerns running an aiohttp server without llhttp:
- behind a proxy: Being more lenient than internet standards require could, depending on deployment environment, assist in request smuggling.
- directly accessible or exposed behind proxies relaying malformed input: the unhandled exception could cause excessive resource consumption on the application server and/or its logging facilities.
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 → 3.9.2
- pip
pip install --upgrade "aiohttp>=3.9.2"- poetry
poetry add "aiohttp>=3.9.2"- uv
uv add "aiohttp>=3.9.2"
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- Low
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
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
Write-ups
Packages
Other links
- github.com/aio-libs/aiohttp/security/advisories/GHSA-8qpw-xqxj-h4r2
- github.com/aio-libs/aiohttp/security/advisories/GHSA-gfw2-4jvh-wgfg
- github.com/aio-libs/aiohttp/pull/3235
- github.com/aio-libs/aiohttp/pull/8074
- github.com/aio-libs/aiohttp/pull/8074/files
- github.com/aio-libs/aiohttp/commit/33ccdfb0a12690af5bb49bda2319ec0907fa7827
- github.com/pypa/advisory-database/tree/main/vulns/aiohttp/PYSEC-2024-26.yaml
- lists.debian.org/debian-lts-announce/2025/02/msg00002.html
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ICUOC…
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXWVZ…
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ICUOC…
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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