Bug 2517043 (CVE-2026-74469)

Summary: CVE-2026-74469 kernel: sctp: prevent peer transport count overflow
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Stream Control Transmission Protocol (SCTP) implementation within the Linux kernel. An integer overflow occurs when the `transport_count` for an association exceeds its 16-bit limit, causing it to wrap around to zero. This allows a diagnostic dump to write 8 MiB of peer addresses beyond the intended memory buffer, leading to an out-of-bounds write. This memory corruption can result in a denial of service (DoS) due to system instability or crashes.
 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 2026-08-15 12:46:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

sctp: prevent peer transport count overflow

sctp_assoc_add_peer() increments the association's 16-bit transport_count
for every new unique peer. Adding the 65,536th transport wraps the count to
zero.

SCTP sock_diag uses transport_count to reserve the INET_DIAG_PEERS payload,
then copies one sockaddr_storage for every entry in transport_addr_list.
After the wrap, a diagnostic dump reserves an empty payload and writes
8 MiB of peer addresses past the skb tail.

Reject a new unique peer when transport_count has reached U16_MAX. Perform
the check after the existing-peer lookup so a duplicate address continues
to return its existing transport at the limit.
Comment 1 Mauro Matteo Cascella 2026-08-19 18:10:36 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081534-CVE-2026-74469-d3f3@gregkh/T