Cyber Resilience

CVE-2025-69227

DoS in Aiohttp ≤ 3.13.3

Published
06 January 2026
Modified
14 January 2026
Patch / advisory
CVSS Score v4 6.6
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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
EPSS Score 0.0034 27th percentile
Risk Priority 40 floored blend · peak EPSS

Summary

CVE-2025-69227 is a medium-severity Infinite Loop (CWE-835) vulnerability in Aiohttp Aiohttp. Its CVSS base score is 6.6 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 27th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-69227 affects AIOHTTP, an asynchronous HTTP client/server framework for asyncio and Python, in versions 3.13.2 and prior. The vulnerability enables an infinite loop when assert statements are bypassed during POST body processing, leading to a denial-of-service (DoS) condition. This issue manifests only if Python optimizations are enabled via the -O flag or PYTHONOPTIMIZE=1 environment variable, and the application includes a handler that invokes the Request.post() method. It is classified under CWE-835 (Infinite Loop) with a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

An unauthenticated attacker with network access can exploit this by sending a specially crafted POST request to a vulnerable endpoint. No user interaction or privileges are required, allowing remote exploitation against affected servers. Successful exploitation triggers the infinite loop, consuming excessive CPU resources and rendering the application unresponsive, resulting in high-impact availability disruption without compromising confidentiality or integrity.

The issue is addressed in AIOHTTP version 3.13.3. Security practitioners should upgrade to this patched release immediately. Additional details are available in the official GitHub security advisory (GHSA-jj3x-wxrx-4x23) and the fixing commit (bc1319ec3cbff9438a758951a30907b072561259).

EU & UK References

Vulnerability Data

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Versions 3.13.2 and below allow for an infinite loop to occur when assert statements are bypassed, resulting in a DoS attack when processing a POST body. If optimizations are…

more

enabled (-O or PYTHONOPTIMIZE=1), and the application includes a handler that uses the Request.post() method, then an attacker may be able to execute a DoS attack with a specially crafted message. This issue is fixed in version 3.13.3.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-30251Same product: Aiohttp Aiohttp
CVE-2026-54278Same product: Aiohttp Aiohttp
CVE-2026-54280Same product: Aiohttp Aiohttp
CVE-2026-34516Same product: Aiohttp Aiohttp
CVE-2025-69228Same product: Aiohttp Aiohttp
CVE-2025-69229Same product: Aiohttp Aiohttp
CVE-2025-69223Same product: Aiohttp Aiohttp
CVE-2024-52303Same product: Aiohttp Aiohttp
CVE-2026-54273Same product: Aiohttp Aiohttp
CVE-2026-22815Same product: Aiohttp Aiohttp

Affected Assets

aiohttp
aiohttp
≤ 3.13.3

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover unreachable loop exit conditions through static analysis, fuzzing, or execution tracing.

Flaw remediation processes identify and correct infinite-loop defects reported from testing or operations.

Requiring documented development processes and secure coding standards reduces introduction of loops whose termination conditions are unreachable.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices (reviews, testing, static analysis) directly prevent introduction of infinite-loop defects.

ID.RA-01 partial match
prevents

Static analysis and vuln scanning during asset assessment can detect unreachable loop exits.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can uncover infinite-loop conditions before release.

prevents

Secure development life cycle mandates practices that can detect and prevent infinite-loop defects.

prevents

Application security requirements can specify loop-termination rules, indirectly reducing the weakness.

prevents

Secure coding standards directly address loop termination and prevent infinite loops.

none

Secure architecture principles encourage designs that avoid unreachable exit conditions.

none

Change management can require review of loop logic when code is modified.

References