CVE-2026-53239

xfrm: policy: fix use-after-free on inexact bin in xfrm_policy_bysel_ctx()

State: Published
Severity: 7.8 High
Published: Jun 25, 2026
Updated: Oct 19, 2026
Reserved: Jun 9, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

xfrm: policy: fix use-after-free on inexact bin in xfrm_policy_bysel_ctx()

Fix the race by pruning the bin while still holding xfrm_policy_lock, before dropping it. Use __xfrm_policy_inexact_prune_bin() directly since the lock is already held. The wrapper xfrm_policy_inexact_prune_bin() becomes unused and is removed.

Race:

CPU0 (XFRM_MSG_DELPOLICY) CPU1 (XFRM_MSG_NEWSPDINFO) ========================== ========================== xfrm_policy_bysel_ctx(): spin_lock_bh(xfrm_policy_lock) bin = xfrm_policy_inexact_lookup() __xfrm_policy_unlink(pol) spin_unlock_bh(xfrm_policy_lock) xfrm_policy_kill(ret) // wide window, lock not held xfrm_hash_rebuild(): spin_lock_bh(xfrm_policy_lock) __xfrm_policy_inexact_flush(): kfree_rcu(bin) // bin freed spin_unlock_bh(xfrm_policy_lock) xfrm_policy_inexact_prune_bin(bin) // UAF: bin is freed

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Affected Products

Product	Versions
LinuxLinux	6be3b0db6db82cf056a72cc18042048edd27f8ee to before 8fc536e9f6856230f19c7d13e71af064b6a77b22Affected 6be3b0db6db82cf056a72cc18042048edd27f8ee to before c4c1ea36d83bf3c4569468ca5b8b614fda1bf821Affected 6be3b0db6db82cf056a72cc18042048edd27f8ee to before 25c8c7fb3b0b9668c7d05e209f58c158d2b020c7Affected 6be3b0db6db82cf056a72cc18042048edd27f8ee to before 42827d03f8009a6a218bacab153e21f39d6a121cAffected 6be3b0db6db82cf056a72cc18042048edd27f8ee to before 88697cf980222d5906a37bf47662dac0732e2a0fAffected 6be3b0db6db82cf056a72cc18042048edd27f8ee to before b5316e2b8614a87d8736941972441cb47bfd4491Affected 6be3b0db6db82cf056a72cc18042048edd27f8ee to before ec82ea4eb220164d854f8734ca5a35e23e577b94Affected 6be3b0db6db82cf056a72cc18042048edd27f8ee to before 7f2d76c9c03257c0782afef9d95321fa04096f60Affected
LinuxLinux	5.0Affected before 5.0Not affected 5.10.259 through 5.10.Not affected 5.15.210 through 5.15.Not affected 6.1.176 through 6.1.Not affected 6.6.143 through 6.6.Not affected 6.12.94 through 6.12.Not affected 6.18.36 through 6.18.Not affected 7.0.13 through 7.0.*Not affected 7.1 and laterNot affected

Product

Versions

LinuxLinux

6be3b0db6db82cf056a72cc18042048edd27f8ee to before 8fc536e9f6856230f19c7d13e71af064b6a77b22Affected
6be3b0db6db82cf056a72cc18042048edd27f8ee to before c4c1ea36d83bf3c4569468ca5b8b614fda1bf821Affected
6be3b0db6db82cf056a72cc18042048edd27f8ee to before 25c8c7fb3b0b9668c7d05e209f58c158d2b020c7Affected
6be3b0db6db82cf056a72cc18042048edd27f8ee to before 42827d03f8009a6a218bacab153e21f39d6a121cAffected
6be3b0db6db82cf056a72cc18042048edd27f8ee to before 88697cf980222d5906a37bf47662dac0732e2a0fAffected
6be3b0db6db82cf056a72cc18042048edd27f8ee to before b5316e2b8614a87d8736941972441cb47bfd4491Affected
6be3b0db6db82cf056a72cc18042048edd27f8ee to before ec82ea4eb220164d854f8734ca5a35e23e577b94Affected
6be3b0db6db82cf056a72cc18042048edd27f8ee to before 7f2d76c9c03257c0782afef9d95321fa04096f60Affected

LinuxLinux

5.0Affected
before 5.0Not affected
5.10.259 through 5.10.*Not affected
5.15.210 through 5.15.*Not affected
6.1.176 through 6.1.*Not affected
6.6.143 through 6.6.*Not affected
6.12.94 through 6.12.*Not affected
6.18.36 through 6.18.*Not affected
7.0.13 through 7.0.*Not affected
7.1 and laterNot affected

References

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