high CVSS 7.5

CVE-2026-54280·Python vulnerability

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, payload resources are not closed correctly when a client disconnects in the middle of a write. If a payload is using an open file or similar limited resource, then an attacker may be able to cause resource starvation temporarily until garbage collection or similar closes the file. This vulnerability is fixed in 3.14.1.

Severity
high
Software
Python
Fixed in
3.14.1
Published
2026-06-22

Affected versions

Until: 3.14.1

Fixed in: 3.14.1

How to fix this CVE

Update Python's aiohttp library to version 3.14.1 or later to prevent resource exhaustion when clients disconnect during payload writes. This fix ensures that file handles and similar limited resources are properly released even when connections are interrupted unexpectedly. Administrators should test the update in a staging environment before deploying to production systems.

sudo dnf update python3-aiohttp

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check the installed aiohttp version by running: python3 -c "import aiohttp; print(aiohttp.__version__)"
  2. Step 2: Verify your application uses aiohttp by checking import statements: grep -r "import aiohttp" /path/to/your/app
  3. Step 3: Monitor system resource usage and file descriptor limits during client disconnections: lsof -p $(pgrep -f 'your_aiohttp_app') | wc -l
  4. Step 4: Confirm the fix by re-running the version check after patching and verifying the output is 3.14.1 or higher

FAQ

What is CVE-2026-54280?

This vulnerability affects aiohttp's handling of payload resources when a client abruptly terminates the connection during data transmission. File descriptors and other limited system resources fail to release promptly, leading to potential resource starvation on the server.

Is CVE-2026-54280 being actively exploited?

No, according to CISA's KEV catalog, CVE-2026-54280 is not currently being exploited in the wild, and no public exploits are available.

What versions of Python/aiohttp are affected by CVE-2026-54280?

All versions of aiohttp prior to 3.14.1 are vulnerable. The vulnerability is present in the aiohttp library itself, regardless of the underlying Python version, though Python 3.6+ with aiohttp is most commonly affected.

How do I check if my server is vulnerable to CVE-2026-54280?

Run 'python3 -c "import aiohttp; print(aiohttp.__version__)"' and compare against version 3.14.1. If the installed version is lower than 3.14.1, your server is vulnerable.

Does Defensia detect CVE-2026-54280?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If aiohttp is installed on a monitored server, CVE-2026-54280 will appear in your dashboard with remediation steps.

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References

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