Bug 2501933 (CVE-2026-54464)

Summary:	CVE-2026-54464 websocket-driver: websocket-driver: Denial of Service due to oversized decompressed WebSocket messages
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akostadi, amasferr, anthomas, dmayorov, ehelms, eshamard, ggainey, jlledo, jpasqual, juwatts, jvasik, kaycoth, mdellweg, mhulan, nmoumoul, osousa, pantinor, pcreech, rblanco, rchan, smallamp, tmalecek, tsedmik
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the `websocket-driver` library. When used with the `permessage-deflate` extension, a remote attacker can send compressed WebSocket messages that, upon decompression, exceed the configured maximum message size. This occurs because the size limit is checked against the compressed data rather than the decompressed data. This can lead to a denial of service (DoS) due to excessive resource consumption in applications accepting these larger-than-expected messages.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-17 21:02:10 UTC

### Impact

If this library is used in tandem with the `permessage-deflate` extension, a
WebSocket server or client can be made to accept messages that are larger than
the configured maximum message size. This is because this limit is checked
against the message frames' length headers, which give the size of the
compressed data, not the size after decompression. This can lead to applications
accepting larger messages than expected and exceeding their intended resource
usage.

### Patches

The issue has been patched in version 0.8.1, by checking the length of messages
after they are processed by incoming extensions. All users should upgrade to
this version.

### Workarounds

No known workarounds exist.

### Acknowledgements

This issue was discovered and reported by Pranjali Thakur, DepthFirst Security
Research Team.