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CVE-2026-54274 aio-libs CVE debrief

CVE-2026-54274 is a vulnerability in the AIOHTTP asynchronous HTTP client/server framework for asyncio and Python. An attacker can bypass the usual size limits on memory use by sending large incomplete WebSocket frame payloads. The vulnerability was fixed in version 3.14.1. This issue has a CVSS score of 6.6 and a severity of MEDIUM. The CVE was published on 2026-06-22T18:16:45.877Z and modified on 2026-06-26T19:37:06.147Z.

Vendor
aio-libs
Product
aiohttp
CVSS
MEDIUM 6.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-22
Original CVE updated
2026-06-26
Advisory published
2026-06-22
Advisory updated
2026-06-26

Who should care

Defenders of applications using AIOHTTP should review their inventory and ensure they are using version 3.14.1 or later to mitigate this vulnerability. This is particularly important for those with exposure to untrusted WebSocket connections. Monitoring for unusual memory usage patterns in AIOHTTP applications may also be warranted.

Technical summary

CVE-2026-54274 is a vulnerability in AIOHTTP's handling of WebSocket frame payloads. When an attacker sends large incomplete WebSocket frame payloads, it may be possible to bypass the usual size limits on memory use. This could potentially lead to memory exhaustion attacks. The vulnerability is fixed in AIOHTTP version 3.14.1. The Common Vulnerability Scoring System (CVSS) score for this vulnerability is 6.6, indicating a medium severity level. The CVSS vector is CVSS: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.

Defensive priority

Defenders should prioritize updating AIOHTTP to version 3.14.1 or later. Monitoring for unusual memory usage patterns in AIOHTTP applications may also be warranted.

Recommended defensive actions

  • Update AIOHTTP to version 3.14.1 or later
  • Review application inventory for AIOHTTP usage
  • Monitor AIOHTTP applications for unusual memory usage patterns
  • Consider implementing WebSocket connection rate limiting
  • Implement additional memory usage monitoring for AIOHTTP applications

Evidence notes

The CVE-2026-54274 vulnerability was identified in the AIOHTTP library. The vulnerability allows for a potential bypass of memory use size limits through large incomplete WebSocket frame payloads. The issue has been fixed in version 3.14.1. Evidence from the NVD and CVE.org confirms the details of this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-54274 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-54274

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-54274 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-54274

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.