Quick answers
- Is CVE-2026-54273 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-54273 being exploited in the wild.
- How severe is CVE-2026-54273?
- Medium severity, with a CVSS score of 4, published 22 June 2026.
- Which products and versions are affected?
- aiohttp (PyPI) <= 3.14.0, ECOSYSTEM:introduced=0,fixed=3.14.1.
- Is there a fix for CVE-2026-54273?
- Yes. aiohttp (PyPI): upgrade to 3.14.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-54273 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-54273?
- Check whether you run aiohttp (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- aiohttp (PyPI): upgrade to 3.14.1 or later
pip install "aiohttp>=3.14.1"
Technical details
A resource exhaustion vulnerability exists in AIOHTTP's HTTP/1.1 parser due to the lack of a limit on the number of parsed-but-unhandled pipelined requests buffered per connection. By sending a continuous stream of pipelined requests, a remote unauthenticated attacker can force the server to allocate an unbounded amount of memory to queue these requests while the handler is busy. This leads to a Denial of Service (DoS) condition via memory exhaustion. The fix, introduced in version 3.14.1, implements a bounded queue that pauses the transport once an internal limit is reached, resuming only as the request handler drains the backlog.
Affected products
- aio-libs aiohttp < 3.14.1
Identifiers
- CVE-2026-54273
- GHSA-4fvr-rgm6-gqmc
- PYSEC-2026-2107
Timeline
- 2026-06-07: patched: Fix committed to repository
- 2026-06-08: advisory: GitHub Security Advisory published
- 2026-06-22: disclosed: NVD publication date