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9.8 Critical

CVE-2025-38708 In the Linux kernel, the following vulnerability has been resolved: drbd: add missing kref_get in handle_write_conflicts…

Description

In the Linux kernel, the following vulnerability has been resolved: drbd: add missing kref_get in handle_write_conflicts With `two-primaries` enabled, DRBD tries to detect "concurrent" writes and handle write conflicts, so that even if you write to the same sector simultaneously on both nodes, they end up with the identical data once the writes are completed. In handling "superseeded" writes, we forgot a kref_get, resulting in a premature drbd_destroy_device and use after free, and further to kernel crashes with symptoms. Relevance: No one should use DRBD as a random data generator, and apparently all users of "two-primaries" handle concurrent writes correctly on layer up. That is cluster file systems use some distributed lock manager, and live migration in virtualization environments stops writes on one node before starting writes on the other node. Which means that other than for "test cases", this code path is never taken in real life. FYI, in DRBD 9, things are handled differently nowadays. We still detect "write conflicts", but no longer try to be smart about them. We decided to disconnect hard instead: upper layers must not submit concurrent writes. If they do, that's their fault.

Affected products and versions

Product Affected versions Fixed in
Linux 6.17 earliest → < 6.17 6.17
Linux 6.16 earliest → < 6.16.2 6.16.2
Linux 6.15 earliest → < 6.15.11 6.15.11
Linux 6.12 earliest → < 6.12.43 6.12.43
Linux 6.6 earliest → < 6.6.103 6.6.103
Linux 6.1 earliest → < 6.1.149 6.1.149
Linux 5.15 earliest → < 5.15.190 5.15.190
Linux 5.10 earliest → < 5.10.241 5.10.241
Linux 5.4 earliest → < 5.4.297 5.4.297
Show the 5 other branches
Product Affected versions Fixed in
Linux 4.5 No fix stated
SIMATIC CN 4100 5.0 earliest → < 5.0 5.0
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP 3.1 3.1.5 → latest No fix stated
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP 3.1 3.1.5 → latest No fix stated
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP 3.1 3.1.5 → latest No fix stated

References

Timeline

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