CVE-2026-53239
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.17% probability · 7th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/25c8c7fb3b0b9668c7d05e209f58c158d2b020c7Patch
- https://git.kernel.org/stable/c/42827d03f8009a6a218bacab153e21f39d6a121cPatch
- https://git.kernel.org/stable/c/7f2d76c9c03257c0782afef9d95321fa04096f60Patch
- https://git.kernel.org/stable/c/88697cf980222d5906a37bf47662dac0732e2a0fPatch
- https://git.kernel.org/stable/c/8fc536e9f6856230f19c7d13e71af064b6a77b22Patch
- https://git.kernel.org/stable/c/b5316e2b8614a87d8736941972441cb47bfd4491Patch
- https://git.kernel.org/stable/c/c4c1ea36d83bf3c4569468ca5b8b614fda1bf821Patch
- https://git.kernel.org/stable/c/ec82ea4eb220164d854f8734ca5a35e23e577b94Patch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.