CVE-2023-47641 | Inconsistent interpretation of `Content-Length` vs. `Transfer-Encoding` in aiohttp

Exp

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Affected versions of aiohttp have a security vulnerability regarding the inconsistent interpretation of the http protocol. HTTP/1.1 is a persistent protocol, if both Content-Length(CL) and Transfer-Encoding(TE) header values are present 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. 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 an attacker could combine it to redirect random users to another website and log the request. This vulnerability has been addressed in release 3.8.0 of aiohttp. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Published: 2023-11-14 Last update: 2025-11-03 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-47641 is rated Exploit Available (50/100): CVSS Low severity, with medium exploitation likelihood (EPSS 0.36%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-47641

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-47641

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-25 0.32% 0.36% +0.04%
2 2026-03-15 0.16% 0.32% +0.16%
3 2025-11-21 — 0.16% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-47641

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.4 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.6 1.4 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 2.5 [email protected]

Weakness enumeration for CVE-2023-47641

GitHub Security Advisory for CVE-2023-47641

GHSA-xx9p-xxvh-7g8j · Severity: low · Ecosystem: pip — Aiohttp has inconsistent interpretation of `Content-Length` vs. `Transfer-Encoding` differing in C and Python fallbacks

OS Trackers for CVE-2023-47641

vendor priority summary link
debian not yet assigned CVE-2023-47641 not yet assigned priority: Debian including 1 source packages (python-aiohttp), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-47641
gentoo normal CVE-2023-47641: 1 GLSA(s) (202408-11), 1 atom(s) (dev-python/aiohttp); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-47641
redhat low — https://access.redhat.com/security/cve/CVE-2023-47641
suse medium CVE-2023-47641 severity moderate: SUSE including 11 source package names (python-aiohttp, python-aiohttp-doc-3.6.0-150100.3.12.1, …), 86 product×package rows across 74 product lines (Image SLES15-SP3-BYOS-Azure, Image SLES15-SP3-HPC-BYOS-Azure, … (74 product lines)): Fixed 84, Known Not Affected 2. https://www.suse.com/security/cve/CVE-2023-47641/
ubuntu medium CVE-2023-47641 medium priority: Ubuntu including 1 source packages (python-aiohttp), 12 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 7, needs-triage 3, ignored 1, released 1. https://ubuntu.com/security/CVE-2023-47641

Affected software / configurations for CVE-2023-47641

Vendor Product Version Raw CPE
aiohttp aiohttp < 3.8.0 cpe:2.3:a:aiohttp:aiohttp:*:*:*:*:*:*:*:*

References for CVE-2023-47641

cvelogic Threat Intelligence