--- id: CVE-2026-53239 title: |- 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 summary: |- 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. Us… severity: high cvss: 7.8 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H' cwe: - CWE-416 - CWE-364 vendor: linux product: linux_kernel affected: - 'linux_kernel >= 5.0, < 5.10.259' - 'linux_kernel >= 5.11, < 5.15.210' - 'linux_kernel >= 5.16, < 6.1.176' - 'linux_kernel >= 6.2, < 6.6.143' - 'linux_kernel >= 6.7, < 6.12.94' - 'linux_kernel >= 6.13, < 6.18.36' - 'linux_kernel >= 6.19, < 7.0.13' - linux_kernel = 7.1 patched: - linux_kernel 7.0.13 published: '2026-06-25' updated: '2026-09-08' sourceUpdated: '2026-09-08T09:18:15.057' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53239' references: - url: 'https://git.kernel.org/stable/c/25c8c7fb3b0b9668c7d05e209f58c158d2b020c7' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/42827d03f8009a6a218bacab153e21f39d6a121c' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/7f2d76c9c03257c0782afef9d95321fa04096f60' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/88697cf980222d5906a37bf47662dac0732e2a0f' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/8fc536e9f6856230f19c7d13e71af064b6a77b22' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/b5316e2b8614a87d8736941972441cb47bfd4491' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/c4c1ea36d83bf3c4569468ca5b8b614fda1bf821' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/ec82ea4eb220164d854f8734ca5a35e23e577b94' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html' label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53239.json - url: 'https://access.redhat.com/security/cve/CVE-2026-53239' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2492779' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-53239' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53239' - url: >- https://lore.kernel.org/linux-cve-announce/2026062510-CVE-2026-53239-8ebc@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:67471' - url: 'https://access.redhat.com/errata/RHSA-2026:68570' - url: 'https://access.redhat.com/errata/RHSA-2026:68531' - url: 'https://access.redhat.com/errata/RHSA-2026:68532' tags: - nvd - cve.org - csaf - vex - red-hat epss: 0.00128 epssPercentile: 0.02788 ingestedAt: '2026-09-08T15:33:26.944Z' scores: nvd: 7.8 vendor: 7 --- ## Overview 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 ## Affected - `linux_kernel >= 5.0, < 5.10.259` - `linux_kernel >= 5.11, < 5.15.210` - `linux_kernel >= 5.16, < 6.1.176` - `linux_kernel >= 6.2, < 6.6.143` - `linux_kernel >= 6.7, < 6.12.94` - `linux_kernel >= 6.13, < 6.18.36` - `linux_kernel >= 6.19, < 7.0.13` - `linux_kernel = 7.1` ## Remediation Upgrade past the affected range: - `linux_kernel 7.0.13` ## Vendor advisories - **RHSA-2026:67471** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67471) - **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9 · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53239.json) - **RHSA-2026:68570** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68570) - **RHSA-2026:68531** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68531) - **RHSA-2026:68532** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68532)