Linux Kernel up to 7.1.8 VXLAN vxlan_changelink use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k1.29-

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.8 and classified as very critical. Affected by this issue is the function vxlan_changelink of the component VXLAN. Executing a manipulation can lead to use after free. The identification of this vulnerability is CVE-2026-74615. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.1.8 and classified as very critical. This vulnerability affects the function vxlan_changelink of the component VXLAN. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In 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]>

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-74615 since 08/15/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 08/22/2026).

Upgrading to version 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, 6.18.45 or 7.1.9 eliminates this vulnerability. Applying the patch be44d79d14d7f9ae7c8ffb7272142005341b5123/26c179d47403d2f919ee914cc02c31d896b59fee/9dc561f0522c35bdd66e0646a748814a138ec4ca/619dd29045e439d0b0f8c6d4fec1af447a050680/6b095e99b9e67ea31f0c4b00260e010898253519/46bb297ad77680e009244f067f27d51cf5b8c7cf/6b4119af544996a545cf84b16f1dbce829ba0de8/b37971686ec59fb027fa4910ba16805e68fddb97 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.265/5.15.216/6.1.183/6.6.152/6.12.104/6.18.45/7.1.9
Patch: be44d79d14d7f9ae7c8ffb7272142005341b5123/26c179d47403d2f919ee914cc02c31d896b59fee/9dc561f0522c35bdd66e0646a748814a138ec4ca/619dd29045e439d0b0f8c6d4fec1af447a050680/6b095e99b9e67ea31f0c4b00260e010898253519/46bb297ad77680e009244f067f27d51cf5b8c7cf/6b4119af544996a545cf84b16f1dbce829ba0de8/b37971686ec59fb027fa4910ba16805e68fddb97

Timelineinfo

08/15/2026 CVE reserved
08/22/2026 +7 days Advisory disclosed
08/22/2026 +0 days VulDB entry created
08/22/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74615 (🔒)
GCVE (CVE): GCVE-0-2026-74615
GCVE (VulDB): GCVE-100-394384

Entryinfo

Created: 08/22/2026 18:05
Changes: 08/22/2026 18:05 (59)
Complete: 🔍
Cache ID: 216::103

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