CVE-2026-68297

CVE Details

Release Date:2026-08-10
Impact:Important What is this?

Description


In the Linux kernel, the following vulnerability has been resolved: tipc: fix u16 MTU truncation in media and bearer MTU validation Both TIPC_NL_MEDIA_SET and TIPC_NL_BEARER_SET accept user-supplied MTU values but only enforce a minimum bound, not a maximum. When a user sets the MTU to a value exceeding U16_MAX (65535), it passes validation but is silently truncated when assigned to u16 fields l->mtu and l->advertised_mtu in tipc_link_create(). Values like 65536 (0x10000) truncate to 0, causing a division by zero in tipc_link_set_queue_limits() which computes TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE). Other overflowing values (e.g. 65537-131071) produce small incorrect MTU values, resulting in link malfunction behaviors. Crash stack (triggered as unprivileged user via user namespace): tipc_link_set_queue_limits net/tipc/link.c:2531 tipc_link_create net/tipc/link.c:520 tipc_node_check_dest net/tipc/node.c:1279 tipc_disc_rcv net/tipc/discover.c:252 tipc_rcv net/tipc/node.c:2129 tipc_udp_recv net/tipc/udp_media.c:392 Two independent paths lack the upper bound check: 1. tipc_udp_mtu_bad() -- called from __tipc_nl_media_set() (MEDIA_SET) 2. inline check in __tipc_nl_bearer_set() at bearer.c:1160 (BEARER_SET) Fix both by rejecting MTU values above U16_MAX.

See more information about CVE-2026-68297 from MITRE CVE dictionary and NIST NVD


NOTE: The following CVSS metrics and score provided are preliminary and subject to review.


CVSS v3 metrics

Base Score: 5.5
Vector String: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version: 3.1
Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality Impact: None
Integrity Impact: None
Availability Impact: High

Errata information


PlatformErrataRelease Date
Oracle Linux version 10 (kernel-uek) ELSA-2026-5002482026-09-04
Oracle Linux version 8 (kernel-uek) ELSA-2026-5002492026-09-04
Oracle Linux version 9 (kernel-uek) ELSA-2026-5002482026-09-04
Oracle Linux version 9 (kernel-uek) ELSA-2026-5002492026-09-04


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