CVE-2026-97611

net: openvswitch: fix use-after-free of the flow table mask array

HIGH
7.8
CVSS Score
Published: September 25, 2026 at 10:22 AM UTC
Updated: October 19, 2026 at 10:17 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%

Description

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: fix use-after-free of the flow table mask array tbl_mask_array_realloc() retires the old mask_array before it stops being reachable: old = ovsl_dereference(tbl->mask_array); if (old) { ... call_rcu(&old->rcu, mask_array_rcu_cb); } rcu_assign_pointer(tbl->mask_array, new); call_rcu() only waits for read-side critical sections already in flight. tbl->mask_array still points at old between the call_rcu() and the rcu_assign_pointer(), so a reader entering ovs_flow_tbl_lookup_stats() in that window picks up old in a fresh critical section that the pending grace period does not cover. tbl_mask_array_realloc() runs in process context under ovs_mutex, so the window is preemptible and can outlast the grace period. Then mask_array_rcu_cb() frees old before the swap runs: BUG: KASAN: slab-use-after-free in flow_lookup.constprop.0+0x2bf/0x2f0 Read of size 8 at addr ffff888020b3e018 by task poc/741 flow_lookup.constprop.0+0x2bf/0x2f0 ovs_flow_tbl_lookup_stats+0x4a3/0x5c0 ovs_dp_process_packet+0x19c/0x710 ovs_vport_receive+0x243/0x390 internal_dev_xmit+0x81/0x170 Freed by task 728: kfree+0x16a/0x4e0 rcu_core+0x853/0x1030 Publish the new array before retiring the old one. The kfree_rcu() that call_rcu() replaced ran after the swap.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.9eac87c413bf9794c14d488998a5265ea5b32f04e
Vendor states this is fixed in 017dbbf0d6c319a487f68e22f56d91fc787d5525 (fixed)
Vendor states this is fixed in 035e9c3722067648a99010711d0ce81f42572ef4 (fixed)
Vendor states this is fixed in 4016ead17acd75312c066ecd47c4b7f0a81ceaa2 (fixed)
Vendor states this is fixed in 4c98b492e9ed63f9ca3e23566d9a6a4f235944f4 (fixed)
Vendor states this is fixed in 76678217cdabc41e3c74c23b45b62086ffb8fe7a (fixed)
Vendor states this is fixed in a0d18d21d48a551f82ee344e50efb8a682161489 (fixed)
Vendor states this is fixed in ba4ba11ed6eb8972c69070417fc27b48deb002e8 (fixed)
Vendor states this is fixed in cd982e11684def5d4a9fcfd5354de09032828414 (fixed)
Vendor states this is fixed in 5.10.271 (unaffected)
Vendor states this is fixed in 5.15.222 (unaffected)
Vendor states this is fixed in 5.9 (unaffected)
Vendor states this is fixed in 6.1.189 (unaffected)
Vendor states this is fixed in 6.12.111 (unaffected)
Vendor states this is fixed in 6.18.53 (unaffected)
Vendor states this is fixed in 6.6.158 (unaffected)
Vendor states this is fixed in 7.2.7 (unaffected)
Vendor states this is fixed in 7.3 (unaffected)
Vendor states this is fixed in 7.3-rc3 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

7.8HIGHLinux
Vector?

Quick Info

StatusRECEIVED

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