CVE-2025-38037
BaseFortify
Publication date: 2025-06-18
Last updated on: 2025-12-18
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | From 3.7 (inc) to 5.4.294 (exc) |
| linux | linux_kernel | From 5.5 (inc) to 5.10.238 (exc) |
| linux | linux_kernel | From 5.11 (inc) to 5.15.185 (exc) |
| linux | linux_kernel | From 5.16 (inc) to 6.1.141 (exc) |
| linux | linux_kernel | From 6.2 (inc) to 6.6.93 (exc) |
| linux | linux_kernel | From 6.7 (inc) to 6.12.31 (exc) |
| linux | linux_kernel | From 6.13 (inc) to 6.14.9 (exc) |
| debian | debian_linux | 11.0 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-NVD-CWE-noinfo |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a data race condition in the Linux kernel's vxlan module. Specifically, the 'used' and 'updated' fields in the Forwarding Database (FDB) entry structure can be accessed concurrently by multiple threads without proper synchronization. This can lead to inconsistent or unexpected behavior, as multiple threads may read and write these fields simultaneously. The issue was detected by the Kernel Concurrency Sanitizer (KCSAN) and can be reproduced using specific commands that simulate concurrent access to the vxlan FDB entries. The fix involves annotating these accesses with READ_ONCE() and WRITE_ONCE() to prevent data races.
How can this vulnerability impact me? :
This vulnerability can cause data races in the Linux kernel's vxlan networking code, potentially leading to unpredictable behavior such as corrupted data in the forwarding database, kernel instability, or crashes. Since vxlan is used for network virtualization, this could impact network reliability and performance on affected systems, especially those using vxlan for overlay networking. However, the description does not specify any direct security exploit such as privilege escalation or information disclosure.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected using the Kernel Concurrency Sanitizer (KCSAN) which reports data races in the vxlan_xmit function. A reproduction script is provided that sets up a vxlan interface and uses the mausezahn tool to generate traffic on specific CPUs to trigger the race condition. The commands include: 1. echo whitelist > /sys/kernel/debug/kcsan 2. echo !vxlan_xmit > /sys/kernel/debug/kcsan 3. ip link add name vx0 up type vxlan id 10010 dstport 4789 local 192.0.2.1 4. bridge fdb add 00:11:22:33:44:55 dev vx0 self static dst 198.51.100.1 5. taskset -c 0 mausezahn vx0 -a own -b 00:11:22:33:44:55 -c 0 -q & 6. taskset -c 2 mausezahn vx0 -a own -b 00:11:22:33:44:55 -c 0 -q &
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation involves applying the patch that annotates the 'used' and 'updated' fields in the FDB entry structure with READ_ONCE() / WRITE_ONCE() to prevent concurrent data races. Until the patch is applied, monitoring for KCSAN reports and avoiding concurrent access patterns that trigger the race condition may help reduce impact. Specific mitigation commands or workarounds are not provided in the available information.