tipc: fix u16 MTU truncation in media and bearer MTU validation
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.
CVE-2026-68297
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-68297
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "901271e0403af638c224987c2a4e55cebade7e91",
"lessThan": "8bfdfe0dbb36a650b7c4dec1aeae078319938a0b",
"versionType": "git"
},
{
"status": "affected",
"version": "901271e0403af638c224987c2a4e55cebade7e91",
"lessThan": "dc4b577a083b361d25e118dc96d8281255ebe22c",
"versionType": "git"
},
{
"status": "affected",
"version": "901271e0403af638c224987c2a4e55cebade7e91",
"lessThan": "dfdfd987f1917c84766e097a6120a1f3f1634940",
"versionType": "git"
},
{
"status": "affected",
"version": "901271e0403af638c224987c2a4e55cebade7e91",
"lessThan": "f02334a9e378f7e07232b26dc3d2ab353339f040",
"versionType": "git"
},
{
"status": "affected",
"version": "901271e0403af638c224987c2a4e55cebade7e91",
"lessThan": "f4013598b69457dbea350df52e52daea6faef8eb",
"versionType": "git"
},
{
"status": "affected",
"version": "901271e0403af638c224987c2a4e55cebade7e91",
"lessThan": "1b8fb5a20508bfb0db854e01214888c761b3a911",
"versionType": "git"
},
{
"status": "affected",
"version": "901271e0403af638c224987c2a4e55cebade7e91",
"lessThan": "c1cda72f6acec02ebd45d913bf8527ff77336ba6",
"versionType": "git"
},
{
"status": "affected",
"version": "901271e0403af638c224987c2a4e55cebade7e91",
"lessThan": "9f29cd8a8e7901a2617c8064ce9f50fc67b97cb8",
"versionType": "git"
}
],
"programFiles": [
"net/tipc/netlink.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.148",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/tipc/netlink.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-68297
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #41689 · Revision 1
- Added to Heist Feed
- Publisher date