tipc: fix UAF in cleanup_bearer() due to premature dst_cache_destroy()
In the Linux kernel, the following vulnerability has been resolved: tipc: fix UAF in cleanup_bearer() due to premature dst_cache_destroy() TIPC UDP media bearer teardown calls dst_cache_destroy() on its replicast caches before calling synchronize_net() to wait for concurrent RCU readers (transmitters) to finish: static void cleanup_bearer(struct work_struct *work) { ... list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) { dst_cache_destroy(&rcast->dst_cache); list_del_rcu(&rcast->list); kfree_rcu(rcast, rcu); } ... dst_cache_destroy(&ub->rcast.dst_cache); udp_tunnel_sock_release(ub->sk); synchronize_net(); ... } This is highly buggy because dst_cache_destroy() immediately frees the per-CPU cache memory (free_percpu()) and releases the cached dst entries without any synchronization. If a concurrent transmitter (e.g., tipc_udp_xmit()) is running on another CPU under RCU protection, it can call dst_cache_get() concurrently, leading to: 1. Use-After-Free on the per-CPU cache pointer itself (crash). 2. "rcuref - imbalanced put()" warning if it attempts to release a dst that was concurrently released by dst_cache_destroy(). Furthermore, calling kfree(ub) immediately after synchronize_net() without closing the socket first (or waiting after closing it) leaves a window where a concurrent receiver (tipc_udp_recv()) could start after synchronize_net(), access ub, and suffer a UAF when kfree(ub) runs. To fix this, we must defer dst_cache_destroy() and kfree(ub) until after we h
CVE-2026-72404
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-2026-72404
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": "e9c1a793210f29f32ee4cf048e04d7d9bb3221cc",
"lessThan": "6aeb4ba4fb098199e13723cfd04d9a749741f731",
"versionType": "git"
},
{
"status": "affected",
"version": "e9c1a793210f29f32ee4cf048e04d7d9bb3221cc",
"lessThan": "6b0e29f7662c237e717f35dad746efe94715d0da",
"versionType": "git"
},
{
"status": "affected",
"version": "e9c1a793210f29f32ee4cf048e04d7d9bb3221cc",
"lessThan": "3827ff67f9fbecd1086e33d23693ef6a1a9c6c38",
"versionType": "git"
},
{
"status": "affected",
"version": "e9c1a793210f29f32ee4cf048e04d7d9bb3221cc",
"lessThan": "1c8393eefa3cadf4ca0b61119ad1321aa32d3c8c",
"versionType": "git"
},
{
"status": "affected",
"version": "e9c1a793210f29f32ee4cf048e04d7d9bb3221cc",
"lessThan": "7116764ca53ff529335d7ab7c364a69f094b23a5",
"versionType": "git"
}
],
"programFiles": [
"net/tipc/udp_media.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.3"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.3",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/tipc/udp_media.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-72404
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #46517 · Revision 1
- Added to Heist Feed
- Publisher date