High 7.8Published Aug 10, 2026

CVE-2026-68297tipc: fix u16 MTU truncation in media and bearer MTU validation

Updated under an hour ago (Oct 28, 2026, 1:40 AM ET)

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Exploited in the last 30 days

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.

CVSS: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-190
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Received
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	901271e0403af638c224987c2a4e55cebade7e91 builds before 8bfdfe0dbb36a650b7c4dec1aeae078319938a0b; from 901271e0403af638c224987c2a4e55cebade7e91 before dc4b577a083b361d25e118dc96d8281255ebe22c; from 901271e0403af638c224987c2a4e55cebade7e91 before dfdfd987f1917c84766e097a6120a1f3f1634940; from 901271e0403af638c224987c2a4e55cebade7e91 before f02334a9e378f7e07232b26dc3d2ab353339f040; from 901271e0403af638c224987c2a4e55cebade7e91 before f4013598b69457dbea350df52e52daea6faef8eb; 901271e0403af638c224987c2a4e55cebade7e91 builds before 1b8fb5a20508bfb0db854e01214888c761b3a911; from 901271e0403af638c224987c2a4e55cebade7e91 before c1cda72f6acec02ebd45d913bf8527ff77336ba6; 901271e0403af638c224987c2a4e55cebade7e91 builds before 9f29cd8a8e7901a2617c8064ce9f50fc67b97cb8	CNA record

References

References

https://git.kernel.org/stable/c/8bfdfe0dbb36a650b7c4dec1aeae078319938a0b
https://git.kernel.org/stable/c/dc4b577a083b361d25e118dc96d8281255ebe22c
https://git.kernel.org/stable/c/dfdfd987f1917c84766e097a6120a1f3f1634940
https://git.kernel.org/stable/c/f02334a9e378f7e07232b26dc3d2ab353339f040
https://git.kernel.org/stable/c/f4013598b69457dbea350df52e52daea6faef8eb
https://git.kernel.org/stable/c/1b8fb5a20508bfb0db854e01214888c761b3a911
https://git.kernel.org/stable/c/c1cda72f6acec02ebd45d913bf8527ff77336ba6
https://git.kernel.org/stable/c/9f29cd8a8e7901a2617c8064ce9f50fc67b97cb8

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.