vxlan: do not arm the ageing timer on a device that is down

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74615
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-22 16:16:34 UTC
Updated2026-08-22 16:16:34 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: vxlan: do not arm the ageing timer on a device that is down vxlan_changelink() arms vxlan->age_timer whenever the requested ageing interval differs from the configured one: if (conf.age_interval != vxlan->cfg.age_interval) mod_timer(&vxlan->age_timer, jiffies); There is no netif_running() test, so the timer is armed even on a device that was never brought up. The only synchronous cancel in the driver is the timer_delete_sync() in vxlan_stop(), which is .ndo_stop. netif_close_many() drops devices without IFF_UP before __dev_close_many() runs, so that cancel is skipped for such a device. vxlan_setup() sets dev->needs_free_netdev = true and age_timer is a member of struct vxlan_dev, so free_netdev() releases the allocation the timer lives in while it is still queued on a timer_base. expire_timers() unlinks the entry before it loads timer->function, so the timer core writes through the freed object's list pointers: BUG: KASAN: slab-use-after-free in __run_timers+0x208/0x654 Write of size 8 at addr ffff00001adace68 by task true/192 __asan_store8+0x84/0xac __run_timers+0x208/0x654 run_timer_softirq+0x154/0x18c Allocated by task 189: alloc_netdev_mqs+0x64/0x720 rtnl_create_link+0x4ac/0x520 rtnl_newlink+0x758/0xd00 Freed by task 191: netdev_release+0x40/0x58 netdev_run_todo+0x4a4/0x8c0 rtnl_dellink+0x200/0x4e8 The rtnl operations involved are netns-scoped, so an unprivileged user can perform them in a new user and network namespace. Arming the timer on a down device never had an effect: vxlan_cleanup() returns early on !netif_running(), and vxlan_open() arms the timer for any non-zero interval once the device is brought up. Add the missing test. Discovered by XBOW, triaged by Baul Lee <[email protected]>

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 40051c4dcad5b374156ad9cceae8d15c0ef1cb95 be44d79d14d7f9ae7c8ffb7272142005341b5123 git Not specified
CNA Linux Linux affected 40051c4dcad5b374156ad9cceae8d15c0ef1cb95 26c179d47403d2f919ee914cc02c31d896b59fee git Not specified
CNA Linux Linux affected 40051c4dcad5b374156ad9cceae8d15c0ef1cb95 9dc561f0522c35bdd66e0646a748814a138ec4ca git Not specified
CNA Linux Linux affected 40051c4dcad5b374156ad9cceae8d15c0ef1cb95 619dd29045e439d0b0f8c6d4fec1af447a050680 git Not specified
CNA Linux Linux affected 40051c4dcad5b374156ad9cceae8d15c0ef1cb95 6b095e99b9e67ea31f0c4b00260e010898253519 git Not specified
CNA Linux Linux affected 40051c4dcad5b374156ad9cceae8d15c0ef1cb95 46bb297ad77680e009244f067f27d51cf5b8c7cf git Not specified
CNA Linux Linux affected 40051c4dcad5b374156ad9cceae8d15c0ef1cb95 6b4119af544996a545cf84b16f1dbce829ba0de8 git Not specified
CNA Linux Linux affected 40051c4dcad5b374156ad9cceae8d15c0ef1cb95 b37971686ec59fb027fa4910ba16805e68fddb97 git Not specified
CNA Linux Linux affected 5.0 Not specified
CNA Linux Linux unaffected 5.0 semver Not specified
CNA Linux Linux unaffected 5.10.265 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.216 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.152 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.104 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.45 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.9 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/9dc561f0522c35bdd66e0646a748814a138ec4ca 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b37971686ec59fb027fa4910ba16805e68fddb97 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6b4119af544996a545cf84b16f1dbce829ba0de8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/be44d79d14d7f9ae7c8ffb7272142005341b5123 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/46bb297ad77680e009244f067f27d51cf5b8c7cf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/619dd29045e439d0b0f8c6d4fec1af447a050680 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/26c179d47403d2f919ee914cc02c31d896b59fee 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6b095e99b9e67ea31f0c4b00260e010898253519 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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