CVE-2025-38031: padata: do not leak refcount in reorder_work

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-18 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: padata: do not leak refcount in reorder_work A recent patch that addressed a UAF introduced a reference count leak: the parallel_data refcount is incremented unconditionally, regardless of the return value of queue_work(). If the work item is already queued, the incremented refcount is never decremented. Fix this by checking the return value of queue_work() and decrementing the refcount when necessary. Resolves: Unreferenced object 0xffff9d9f421e3d80 (size 192): comm "cryptomgr_probe", pid 157, jiffies 4294694003 hex dump (first 32 bytes): 80 8b cf 41 9f 9d ff ff b8 97 e0 89 ff ff ff ff ...A............ d0 97 e0 89 ff ff ff ff 19 00 00 00 1f 88 23 00 ..............#. backtrace (crc 838fb36): __kmalloc_cache_noprof+0x284/0x320 padata_alloc_pd+0x20/0x1e0 padata_alloc_shell+0x3b/0xa0 0xffffffffc040a54d cryptomgr_probe+0x43/0xc0 kthread+0xf6/0x1f0 ret_from_fork+0x2f/0x50 ret_from_fork_asm+0x1a/0x30

Affected products

Debian Linux: 11.0
Linux kernel: from 5.10.235 before 5.10.238; from 5.15.179 before 5.15.185; from 6.1.129 before 6.1.141; from 6.6.76 before 6.6.93; from 6.12.13 before 6.12.31; from 6.13.2 before 6.14.9 — fixed in 5.10.238, 5.15.185, 6.1.141, 6.12.31, 6.14.9, 6.6.93

How to fix

Upgrade to a fixed version: Linux kernel 5.10.238, 5.15.185, 6.1.141, 6.12.31. Check the vendor advisory for mitigations.

References

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