CVE-2025-69227
Published: 06 January 2026
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 Exploit Public-Facing Application (T1190); ranked at the 7.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SI-2 (Flaw Remediation).
Deeper analysis
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
- 🇪🇺 ENISA EUVD: EUVD-2026-1045
Vulnerability details
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 TechniquesAI
Why these techniques?
Remote unauthenticated exploitation of public-facing AIOHTTP server triggers application DoS via crafted POST causing infinite loop.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly remediates the infinite loop flaw in AIOHTTP versions 3.13.2 and prior by requiring timely patching to the fixed version 3.13.3.
Protects against the denial-of-service attack by implementing controls to detect and limit effects of resource exhaustion from the infinite loop triggered by crafted POST requests.
Validates incoming POST body information to block specially crafted inputs that bypass assert statements and induce the infinite loop.