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CVE-2023-47641· NVD / CVE Program· CNA GitHub_M

Inconsistent interpretation of `Content-Length` vs. `Transfer-Encoding` in aiohttp

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.83% (FIRST EPSS); higher than 56.8% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: python-aiohttp (Debian:11) 3.7.4-1+deb11u1; python-aiohttp (Debian:12) 3.8.1-1; python-aiohttp (openSUSE:Tumbleweed) 3.9.3-2.1, 3.14.3-1.1.
  • Severity is disputed: the assigning authority (CNA) scores it 3.4, NVD 6.5.

Low priority for now. Upgrade to python-aiohttp (Debian:11) 3.7.4-1+deb11u1; python-aiohttp (Debian:12) 3.8.1-1; python-aiohttp (openSUSE:Tumbleweed) 3.9.3-2.1, 3.14.3-1.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Nov 14, 2023
Updated
Jun 17, 2026
EPSS
0.8% · 56th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.5
CNA · GitHub_M
3.4
3.1 point gap

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-47641

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
aiohttpaiohttp

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • aiohttp aiohttpbefore 3.8.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • aio-libs aiohttp

    • < 3.8.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:11python-aiohttpbefore 3.7.4-1+deb11u13.7.4-1+deb11u1
Debian:12python-aiohttpbefore 3.8.1-13.8.1-1
openSUSE:Tumbleweedpython-aiohttpbefore 3.9.3-2.13.9.3-2.1
openSUSE:Tumbleweedpython-aiohttpbefore 3.14.3-1.13.14.3-1.1
PyPIaiohttpbefore 3.8.03.8.0
SUSE:Linux Enterprise Module for Public Cloud 15 SP1python-aiohttpbefore 3.6.0-150100.3.12.13.6.0-150100.3.12.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP1python-aiohttpbefore 3.6.0-150100.3.12.13.6.0-150100.3.12.1
SUSE:Linux Enterprise Module for Python 3 15 SP5python-aiohttpbefore 3.9.3-150400.10.14.13.9.3-150400.10.14.1
SUSE:Linux Enterprise Module for Python 3 15 SP5python-aiohttpbefore 3.9.3-150400.10.14.13.9.3-150400.10.14.1

Same product

aiohttp: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-23334aiohttp.web.static(follow_symlinks=True) is vulnerable to directory traversal
    53Plan
  • CVE-2024-52303aiohttp memory leak when middleware is enabled when requesting a resource with a non-allowed method
    34Monitor
  • CVE-2025-69223AIOHTTP's HTTP Parser auto_decompress feature is vulnerable to zip bomb
    30Monitor
  • CVE-2024-30251Denial of service when trying to parse malformed POST requests in aiohttp
    30Monitor
  • CVE-2023-47627Request smuggling in aiohttp
    30Monitor
  • CVE-2023-37276aiohttp vulnerable to HTTP request smuggling
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:python-aiohttp3.8.1-1 · Debian:12Package registry (OSV)
opensuse:python-aiohttp3.6.0-150100.3.12.1 · openSUSE:Leap 15.4Package registry (OSV)
PyPI:aiohttp3.8.0Package registry (OSV)
suse:python-aiohttp3.6.0-150100.3.12.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2023-476270 days apartRequest smuggling in aiohttp
    30Monitor
  • CVE-2023-37276118 days apartaiohttp vulnerable to HTTP request smuggling
    30Monitor
  • CVE-2024-2382976 days apartaiohttp's HTTP parser (the python one, not llhttp) still overly lenient about separators
    26Monitor
  • CVE-2024-52304370 days apartaiohttp vulnerable to request smuggling due to incorrect parsing of chunk extensions
    25Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records