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CVE-2025-53643· NVD / CVE Program· CNA GitHub_M

AIOHTTP is vulnerable to HTTP Request/Response Smuggling through incorrect parsing of chunked trailer sections

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.12.14, the Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request. If a pure Python version of aiohttp is installed (i.e. without the usual C extensions) or AIOHTTP_NO_EXTENSIONS is enabled, then an attacker may be able to execute a request smuggling attack to bypass certain firewalls or proxy protections. Version 3.12.14 contains a patch for this issue.

LowCVSS 1.7 · v4.0—No exploit Fix available
Published
Jul 14, 2025
Updated
Jun 17, 2026
EPSS
0.3% · 24th percentile
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Report tools

JSON

Action score

6

Monitor

Low priority for now.

CVSS
6 / 40 · 1.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
1.7
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U

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

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Affected systems

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 3.12.14

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

    • < 3.12.14affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12python-aiohttpall versions—
Debian:14python-aiohttpbefore 3.12.15-13.12.15-1
openSUSE:Leap 16.0python-aiohttpbefore 3.11.16-160000.3.13.11.16-160000.3.1
openSUSE:Leap 16.0python-Brotlibefore 1.1.0-160000.3.11.1.0-160000.3.1
PyPIaiohttpbefore 3.12.143.12.14
Red Hat:ansible_automation_platform_developer:2.5::el8python3.11-djangobefore 0:4.2.27-1.el8ap0:4.2.27-1.el8ap
Red Hat:ansible_automation_platform_developer:2.5::el8python3.11-urllib3before 0:2.6.3-1.el8ap0:2.6.3-1.el8ap
Red Hat:ansible_automation_platform_developer:2.5::el8receptorbefore 0:1.6.3-1.el8ap0:1.6.3-1.el8ap
Red Hat:ansible_automation_platform_developer:2.5::el9python3.11-djangobefore 0:4.2.27-1.el9ap0:4.2.27-1.el9ap
Red Hat:ansible_automation_platform_developer:2.5::el9receptorbefore 0:1.6.3-1.el9ap0:1.6.3-1.el9ap
Red Hat:ansible_automation_platform_developer:2.6::el9python3.11-djangobefore 0:4.2.27-2.el9ap0:4.2.27-2.el9ap
Red Hat:ansible_automation_platform_developer:2.6::el9python3.11-urllib3before 0:2.6.3-1.el9ap0:2.6.3-1.el9ap
Red Hat:ansible_automation_platform_developer:2.6::el9receptorbefore 0:1.6.3-2.el9ap0:1.6.3-2.el9ap
Red Hat:ansible_automation_platform:2.5::el8automation-controller-venv-towerbefore 0:4.6.25-1.el8ap0:4.6.25-1.el8ap
Red Hat:ansible_automation_platform:2.5::el9automation-controller-venv-towerbefore 0:4.6.25-1.el9ap0:4.6.25-1.el9ap
Red Hat:ansible_automation_platform:2.6::el10receptorbefore 0:1.6.3-2.el10ap0:1.6.3-2.el10ap
Red Hat:ansible_automation_platform:2.6::el9automation-controller-venv-towerbefore 0:4.7.8-1.el9ap0:4.7.8-1.el9ap
Red Hat:ansible_automation_platform:2.6::el9python3.11-protobufbefore 0:4.25.8-1.el9ap0:4.25.8-1.el9ap
Red Hat:ansible_automation_platform:2.6::el9python3.11-protobuf-debuginfobefore 0:4.25.8-1.el9ap0:4.25.8-1.el9ap
Red Hat:ansible_automation_platform:2.6::el9python3.11-protobuf-debugsourcebefore 0:4.25.8-1.el9ap0:4.25.8-1.el9ap
Red Hat:satellite_capsule:6.18::el9python3.12-aiohttpbefore 0:3.13.3-1.el9pc0:3.13.3-1.el9pc
Red Hat:satellite_capsule:6.18::el9python3.12-aiohttp-debuginfobefore 0:3.13.3-1.el9pc0:3.13.3-1.el9pc
Red Hat:satellite_capsule:6.18::el9python3.12-aiohttp-debugsourcebefore 0:3.13.3-1.el9pc0:3.13.3-1.el9pc
Red Hat:satellite_capsule:6.18::el9python3.12-urllib3before 0:2.6.3-1.el9pc0:2.6.3-1.el9pc

+5

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-aiohttp3.12.15-1 · Debian:14Package registry (OSV)
opensuse:python-aiohttp3.9.3-150400.10.33.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:python-Brotli1.1.0-160000.3.1 · openSUSE:Leap 16.0Package registry (OSV)
PyPI:aiohttp3.12.14Package registry (OSV)
red hat:automation-controller-venv-tower0:4.7.8-1.el9ap · Red Hat:ansible_automation_platform:2.6::el9Package registry (OSV)
red hat:python3.11-django0:4.2.27-2.el9ap · Red Hat:ansible_automation_platform_developer:2.6::el9Package registry (OSV)
red hat:python3.11-protobuf0:4.25.8-1.el9ap · Red Hat:ansible_automation_platform:2.6::el9Package registry (OSV)
red hat:python3.11-protobuf-debuginfo0:4.25.8-1.el9ap · Red Hat:ansible_automation_platform:2.6::el9Package registry (OSV)
red hat:python3.11-protobuf-debugsource0:4.25.8-1.el9ap · Red Hat:ansible_automation_platform:2.6::el9Package registry (OSV)
red hat:python3.11-urllib30:2.6.3-1.el9ap · Red Hat:ansible_automation_platform_developer:2.6::el9Package registry (OSV)
red hat:python3.12-aiohttp0:3.13.3-1.el9pc · Red Hat:satellite_capsule:6.18::el9Package registry (OSV)
red hat:python3.12-aiohttp-debuginfo0:3.13.3-1.el9pc · Red Hat:satellite_capsule:6.18::el9Package registry (OSV)
red hat:python3.12-aiohttp-debugsource0:3.13.3-1.el9pc · Red Hat:satellite_capsule:6.18::el9Package registry (OSV)
red hat:python3.12-urllib30:2.6.3-1.el9pc · Red Hat:satellite_capsule:6.18::el9Package registry (OSV)
red hat:receptor0:1.6.3-2.el10ap · Red Hat:ansible_automation_platform:2.6::el10Package registry (OSV)
suse:python-aiohttp3.9.3-150400.10.33.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP4Package registry (OSV)
suse:python-Brotli1.1.0-160000.3.1 · SUSE:Linux Enterprise Server 16.0Package 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-2024-23829532 days apartaiohttp's HTTP parser (the python one, not llhttp) still overly lenient about separators
    26Monitor
  • CVE-2025-69224175 days apartAIOHTTP's Unicode processing of header values could cause parsing discrepancies
    25Monitor
  • CVE-2024-52304238 days apartaiohttp vulnerable to request smuggling due to incorrect parsing of chunk extensions
    25Monitor
  • CVE-2025-69225176 days apartAIOHTTP Regex Mismatch Allows Unicode in ASCII-Only Protocol Fields
    10Monitor

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
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

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

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

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

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

All records