CVE-2026-68297tipc: fix u16 MTU truncation in media and bearer MTU validation
Updated under an hour ago ()
Does this affect you?
It affects Linux. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
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)
- Not given
- 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 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
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
- 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.