{"id":"CVE-2025-38037","title":"vxlan: Annotate FDB data races","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: Annotate FDB data races\n\nThe 'used' and 'updated' fields in the FDB entry structure can be\naccessed concurrently by multiple threads, leading to reports such as\n…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 02a33b1035a307453a1da6ce0a1bf3676be287d7","Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 87d076987a9ba106c83412fcd113656f71af05a1","Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < e033da39fc6abbddab6c29624acef80757f273fa","Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 784b78295a3a58bf052339dd669e6e03710220d3","Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 13cba3f837903f7184d6e9b6137d5165ffe82a8f","Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < a6644aeb8ddf196dec5f8e782293c36f065df4d7","Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 4eceb7eae6ea7c950384c34e6dbbe872c981935f","Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < f6205f8215f12a96518ac9469ff76294ae7bd612","Linux 3.7"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-05T20:48:26.208696Z"},"published":"2025-06-18","updated":"2026-11-05","sourceUpdated":"2026-11-05T20:52:13.124Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-38037","references":[{"url":"https://git.kernel.org/stable/c/02a33b1035a307453a1da6ce0a1bf3676be287d7"},{"url":"https://git.kernel.org/stable/c/87d076987a9ba106c83412fcd113656f71af05a1"},{"url":"https://git.kernel.org/stable/c/e033da39fc6abbddab6c29624acef80757f273fa"},{"url":"https://git.kernel.org/stable/c/784b78295a3a58bf052339dd669e6e03710220d3"},{"url":"https://git.kernel.org/stable/c/13cba3f837903f7184d6e9b6137d5165ffe82a8f"},{"url":"https://git.kernel.org/stable/c/a6644aeb8ddf196dec5f8e782293c36f065df4d7"},{"url":"https://git.kernel.org/stable/c/4eceb7eae6ea7c950384c34e6dbbe872c981935f"},{"url":"https://git.kernel.org/stable/c/f6205f8215f12a96518ac9469ff76294ae7bd612"}],"tags":["cve.org"],"epss":0.00223,"epssPercentile":0.12973,"ingestedAt":"2026-11-05T22:38:31.909Z","slug":"CVE-2025-38037","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: Annotate FDB data races\n\nThe 'used' and 'updated' fields in the FDB entry structure can be\naccessed concurrently by multiple threads, leading to reports such as\n[1]. Can be reproduced using [2].\n\nSuppress these reports by annotating these accesses using\nREAD_ONCE() / WRITE_ONCE().\n\n[1]\nBUG: KCSAN: data-race in vxlan_xmit / vxlan_xmit\n\nwrite to 0xffff942604d263a8 of 8 bytes by task 286 on cpu 0:\n vxlan_xmit+0xb29/0x2380\n dev_hard_start_xmit+0x84/0x2f0\n __dev_queue_xmit+0x45a/0x1650\n packet_xmit+0x100/0x150\n packet_sendmsg+0x2114/0x2ac0\n __sys_sendto+0x318/0x330\n __x64_sys_sendto+0x76/0x90\n x64_sys_call+0x14e8/0x1c00\n do_syscall_64+0x9e/0x1a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nread to 0xffff942604d263a8 of 8 bytes by task 287 on cpu 2:\n vxlan_xmit+0xadf/0x2380\n dev_hard_start_xmit+0x84/0x2f0\n __dev_queue_xmit+0x45a/0x1650\n packet_xmit+0x100/0x150\n packet_sendmsg+0x2114/0x2ac0\n __sys_sendto+0x318/0x330\n __x64_sys_sendto+0x76/0x90\n x64_sys_call+0x14e8/0x1c00\n do_syscall_64+0x9e/0x1a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nvalue changed: 0x00000000fffbac6e -> 0x00000000fffbac6f\n\nReported by Kernel Concurrency Sanitizer on:\nCPU: 2 UID: 0 PID: 287 Comm: mausezahn Not tainted 6.13.0-rc7-01544-gb4b270f11a02 #5\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014\n\n[2]\n #!/bin/bash\n\n set +H\n echo whitelist > /sys/kernel/debug/kcsan\n echo !vxlan_xmit > /sys/kernel/debug/kcsan\n\n ip link add name vx0 up type vxlan id 10010 dstport 4789 local 192.0.2.1\n bridge fdb add 00:11:22:33:44:55 dev vx0 self static dst 198.51.100.1\n taskset -c 0 mausezahn vx0 -a own -b 00:11:22:33:44:55 -c 0 -q &\n taskset -c 2 mausezahn vx0 -a own -b 00:11:22:33:44:55 -c 0 -q &\n\n## Affected\n\n- `Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 02a33b1035a307453a1da6ce0a1bf3676be287d7`\n- `Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 87d076987a9ba106c83412fcd113656f71af05a1`\n- `Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < e033da39fc6abbddab6c29624acef80757f273fa`\n- `Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 784b78295a3a58bf052339dd669e6e03710220d3`\n- `Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 13cba3f837903f7184d6e9b6137d5165ffe82a8f`\n- `Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < a6644aeb8ddf196dec5f8e782293c36f065df4d7`\n- `Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < 4eceb7eae6ea7c950384c34e6dbbe872c981935f`\n- `Linux >= d342894c5d2f8c7df194c793ec4059656e09ca31 < f6205f8215f12a96518ac9469ff76294ae7bd612`\n- `Linux 3.7`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}