net/sched: act_tunnel_key: Defer dst_release to RCU callback
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_tunnel_key: Defer dst_release to RCU callback Fix a race-condition use-after-free in tunnel_key_release_params(). The function releases the metadata_dst of the old params synchronously via dst_release() while deferring the params struct free with kfree_rcu(). A concurrent tunnel_key_act() reader on the datapath may still hold the old params pointer (under rcu_read_lock_bh) and proceed to call dst_clone(¶ms->tcft_enc_metadata->dst) after the writer's dst_release has already pushed the dst's rcuref to RCUREF_DEAD. zdi-disclosures@trendmicro.com produced a poc which i (and Victor) verified that KASAN reports: ================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 BUG: KASAN: slab-use-after-free in atomic_sub_return_release include/linux/atomic/atomic-instrumented.h:326 BUG: KASAN: slab-use-after-free in __rcuref_put include/linux/rcuref.h:109 BUG: KASAN: slab-use-after-free in rcuref_put include/linux/rcuref.h:173 BUG: KASAN: slab-use-after-free in dst_release+0x5b/0x370 net/core/dst.c:168 Write of size 4 at addr ffff88806158de40 by task poc/9388 CPU: 0 UID: 0 PID: 9388 Comm: poc Tainted: G W 7.1.0-rc7 #7 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack
CVE-2026-68377
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-2026-68377
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": "9174c3df1cd181c14913138d50ccbe539bb08335",
"lessThan": "b5931f020b681fdcb9378262d89b61cb3c7ebbf8",
"versionType": "git"
},
{
"status": "affected",
"version": "9174c3df1cd181c14913138d50ccbe539bb08335",
"lessThan": "389d03992dabb80488228e8119b9dd6d0f58e1a6",
"versionType": "git"
},
{
"status": "affected",
"version": "9174c3df1cd181c14913138d50ccbe539bb08335",
"lessThan": "676ad6aa7cec89a08d2a5ce3cd5959e313f29733",
"versionType": "git"
},
{
"status": "affected",
"version": "9174c3df1cd181c14913138d50ccbe539bb08335",
"lessThan": "531dbb5bb98e52ad26be7e90f9f8bec707c5bd0e",
"versionType": "git"
},
{
"status": "affected",
"version": "9174c3df1cd181c14913138d50ccbe539bb08335",
"lessThan": "2200a00ff247f70f5dcdb4e6f14b0d48ddac5467",
"versionType": "git"
},
{
"status": "affected",
"version": "9174c3df1cd181c14913138d50ccbe539bb08335",
"lessThan": "fed1b1ddab41a0e7a462ac690a0c8af6ff793624",
"versionType": "git"
},
{
"status": "affected",
"version": "9174c3df1cd181c14913138d50ccbe539bb08335",
"lessThan": "2791a501da508b704a617b4dba29db54a65bc9f7",
"versionType": "git"
},
{
"status": "affected",
"version": "9174c3df1cd181c14913138d50ccbe539bb08335",
"lessThan": "f1f5c8a3955f8fda3f84ed883ac8daa1847e724c",
"versionType": "git"
},
{
"status": "affected",
"version": "02239e797ac75f89a05622a27d04695f08c1ca89",
"versionType": "git"
},
{
"status": "affected",
"version": "ca9b7a65a2c97579fcdd509d454d48e3a5c49af8",
"versionType": "git"
},
{
"status": "affected",
"version": "4.19.19",
"lessThan": "4.20",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.20.6",
"lessThan": "4.21",
"versionType": "semver"
}
],
"programFiles": [
"net/sched/act_tunnel_key.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.0",
"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/sched/act_tunnel_key.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-68377
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #41708 · Revision 1
- Added to Heist Feed
- Publisher date