CVE-2026-31640
Published: April 24, 2026· Updated: Apr 27, 2026
Official Description
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix use of wrong skb when comparing queued RESP challenge serial
In rxrpc_post_response(), the code should be comparing the challenge serial
number from the cached response before deciding to switch to a newer
response, but looks at the newer packet private data instead, rendering the
comparison always false.
Fix this by switching to look at the older packet.
Fix further[1] to substitute the new packet in place of the old one if
newer and also to release whichever we don't use.
Technical Analysis
CVE-2026-31640 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (3)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-31640 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts