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Fencer Vulns
high 7.8

CVE-2026-31508 json

net: openvswitch: Avoid releasing netdev before teardown completes

published 2026-04-22 6 mo ago modified 2026-10-19 20 d ago also EUVD-2026-24887

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

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

net: openvswitch: Avoid releasing netdev before teardown completes

The patch cited in the Fixes tag below changed the teardown code for OVS ports to no longer unconditionally take the RTNL. After this change, the netdev_destroy() callback can proceed immediately to the call_rcu() invocation if the IFF_OVS_DATAPATH flag is already cleared on the netdev.

The ovs_netdev_detach_dev() function clears the flag before completing the unregistration, and if it gets preempted after clearing the flag (as can happen on an -rt kernel), netdev_destroy() can complete and the device can be freed before the unregistration completes. This leads to a splat like:

[ 998.393867] Oops: general protection fault, probably for non-canonical address 0xff00000001000239: 0000 [#1] SMP PTI [ 998.393877] CPU: 42 UID: 0 PID: 55177 Comm: ip Kdump: loaded Not tainted 6.12.0-211.1.1.el10_2.x86_64+rt #1 PREEMPT_RT [ 998.393886] Hardware name: Dell Inc. PowerEdge R740/0JMK61, BIOS 2.24.0 03/27/2025 [ 998.393889] RIP: 0010:dev_set_promiscuity+0x8d/0xa0 [ 998.393901] Code: 00 00 75 d8 48 8b 53 08 48 83 ba b0 02 00 00 00 75 ca 48 83 c4 08 5b c3 cc cc cc cc 48 83 bf 48 09 00 00 00 75 91 48 8b 47 08 <48> 83 b8 b0 02 00 00 00 74 97 eb 81 0f 1f 80 00 00 00 00 90 90 90 [ 998.393906] RSP: 0018:ffffce5864a5f6a0 EFLAGS: 00010246 [ 998.393912] RAX: ff00000000ffff89 RBX: ffff894d0adf5a05 RCX: 0000000000000000 [ 998.393917] RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff894d0adf5a05 [ 998.393921] RBP: ffff894d19252000 R08: ffff894d19252000 R09: 0000000000000000 [ 998.393924] R10: ffff894d19252000 R11: ffff894d192521b8 R12: 0000000000000006 [ 998.393927] R13: ffffce5864a5f738 R14: 00000000ffffffe2 R15: 0000000000000000 [ 998.393931] FS: 00007fad61971800(0000) GS:ffff894cc0140000(0000) knlGS:0000000000000000 [ 998.393936] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 998.393940] CR2: 000055df0a2a6e40 CR3: 000000011c7fe003 CR4: 00000000007726f0 [ 998.393944] PKRU: 55555554 [ 998.393946] Call Trace: [ 998.393949] <TASK> [ 998.393952] ? show_trace_log_lvl+0x1b0/0x2f0 [ 998.393961] ? show_trace_log_lvl+0x1b0/0x2f0 [ 998.393975] ? dp_device_event+0x41/0x80 [openvswitch] [ 998.394009] ? __die_body.cold+0x8/0x12 [ 998.394016] ? die_addr+0x3c/0x60 [ 998.394027] ? exc_general_protection+0x16d/0x390 [ 998.394042] ? asm_exc_general_protection+0x26/0x30 [ 998.394058] ? dev_set_promiscuity+0x8d/0xa0 [ 998.394066] ? ovs_netdev_detach_dev+0x3a/0x80 [openvswitch] [ 998.394092] dp_device_event+0x41/0x80 [openvswitch] [ 998.394102] notifier_call_chain+0x5a/0xd0 [ 998.394106] unregister_netdevice_many_notify+0x51b/0xa60 [ 998.394110] rtnl_dellink+0x169/0x3e0 [ 998.394121] ? rt_mutex_slowlock.constprop.0+0x95/0xd0 [ 998.394125] rtnetlink_rcv_msg+0x142/0x3f0 [ 998.394128] ? avc_has_perm_noaudit+0x69/0xf0 [ 998.394130] ? __pfx_rtnetlink_rcv_msg+0x10/0x10 [ 998.394132] netlink_rcv_skb+0x50/0x100 [ 998.394138] netlink_unicast+0x292/0x3f0 [ 998.394141] netlink_sendmsg+0x21b/0x470 [ 998.394145] ____sys_sendmsg+0x39d/0x3d0 [ 998.394149] ___sys_sendmsg+0x9a/0xe0 [ 998.394156] __sys_sendmsg+0x7a/0xd0 [ 998.394160] do_syscall_64+0x7f/0x170 [ 998.394162] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 998.394165] RIP: 0033:0x7fad61bf4724 [ 998.394188] Code: 89 02 b8 ff ff ff ff eb bb 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 80 3d c5 e9 0c 00 00 74 13 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 89 54 24 1c 48 89 [ 998.394189] RSP: 002b:00007ffd7e2f7cb8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e [ 998.394191] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fad61bf4724 [ 998.394193] RDX: 0000000000000000 RSI: 00007ffd7e2f7d20 RDI: 0000000000000003 [ 998.394194] RBP: 00007ffd7e2f7d90 R08: 0000000000000010 R09: 000000000000003f [ 998.394195] R10: 000055df11558010 R11: 0000000000000202 R12: 00007ffd7e2 ---truncated---

Patch / fix

  • Linux Linux 5.10.253, 5.15.203, 6.1.168, 6.6.131, 6.12.80, 6.18.21, 6.19.11, 7.0
  • linux Debian 12 6.1.170-1
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.19.11-1

debian advisories DEBIAN-CVE-2026-31508

  • linux Ubuntu 22.04 LTS 5.15.0-186.196
  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1112.119
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1112.122
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1108.114
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1059.67

ubuntu advisories UBUNTU-CVE-2026-31508

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-687.15.1.el9_8
  • rv RHEL 9 5.14.0-687.15.1.el9_8
  • perf RHEL 9 5.14.0-687.15.1.el9_8
  • rtla RHEL 9 5.14.0-687.15.1.el9_8
  • libperf RHEL 9 5.14.0-687.15.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.15.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.15.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.15.1.el9_8

red hat advisories RHSA-2026:25218RHSA-2026:25217RHSA-2026:25028

  • kernel AlmaLinux 9 5.14.0-687.15.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.15.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.15.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.15.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.15.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.15.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.15.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.15.1.el9_8

almalinux advisories ALSA-2026:25217

  • kernel Rocky Linux 9 5.14.0-687.15.1.el9_7.cloud.1.0
  • kernel Rocky Linux 9 5.14.0-687.15.1.el9_8

rocky linux advisories RXSA-2026:25217RLSA-2026:25217

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-31508 updated cvss 7.0

kernel: net: openvswitch: Avoid releasing netdev before teardown completes

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 10 kernel
    affected: no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.6) libperf 5.14.0-570.120.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.120.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.120.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.120.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.120.1.el9_6
    fixed: vendor fix RHSA-2026:25218
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.15.1.el9_8, perf 5.14.0-687.15.1.el9_8, rtla 5.14.0-687.15.1.el9_8, python3-perf 5.14.0-687.15.1.el9_8, kernel-devel-matched 5.14.0-687.15.1.el9_8, kernel-64k-devel-matched 5.14.0-687.15.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:25217
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) rv 5.14.0-427.130.1.el9_4, perf 5.14.0-427.130.1.el9_4, rtla 5.14.0-427.130.1.el9_4, kernel-devel-matched 5.14.0-427.130.1.el9_4, kernel-64k-devel-matched 5.14.0-427.130.1.el9_4, kernel-debug-devel-matched 5.14.0-427.130.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:25028
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) rv 5.14.0-570.120.1.el9_6, perf 5.14.0-570.120.1.el9_6, rtla 5.14.0-570.120.1.el9_6, python3-perf 5.14.0-570.120.1.el9_6, kernel-devel-matched 5.14.0-570.120.1.el9_6, kernel-64k-devel-matched 5.14.0-570.120.1.el9_6, +7 more
    fixed: vendor fix RHSA-2026:25218
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.15.1.el9_8, kernel-64k 5.14.0-687.15.1.el9_8, kernel-core 5.14.0-687.15.1.el9_8, kernel-tools 5.14.0-687.15.1.el9_8, kernel-modules 5.14.0-687.15.1.el9_8, kernel-64k-core 5.14.0-687.15.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:25217
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool 7.3.0-427.130.1.el9_4, kernel 5.14.0-427.130.1.el9_4, kernel-64k 5.14.0-427.130.1.el9_4, kernel-core 5.14.0-427.130.1.el9_4, kernel-tools 5.14.0-427.130.1.el9_4, python3-perf 5.14.0-427.130.1.el9_4, +28 more
    fixed: vendor fix RHSA-2026:25028
show 8 more
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel 5.14.0-570.120.1.el9_6, kernel-64k 5.14.0-570.120.1.el9_6, kernel-core 5.14.0-570.120.1.el9_6, kernel-tools 5.14.0-570.120.1.el9_6, kernel-modules 5.14.0-570.120.1.el9_6, kernel-64k-core 5.14.0-570.120.1.el9_6, +27 more
    fixed: vendor fix RHSA-2026:25218
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.15.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.15.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.15.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.15.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.15.1.el9_8 Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.15.1.el9_8, kernel-rt-64k 5.14.0-687.15.1.el9_8, kernel-rt-core 5.14.0-687.15.1.el9_8, kernel-rt-modules 5.14.0-687.15.1.el9_8, kernel-rt-64k-core 5.14.0-687.15.1.el9_8, kernel-rt-debug-core 5.14.0-687.15.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:25217
  • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt 5.14.0-427.130.1.el9_4, kernel-rt-core 5.14.0-427.130.1.el9_4, kernel-rt-modules 5.14.0-427.130.1.el9_4, kernel-rt-debug-core 5.14.0-427.130.1.el9_4, kernel-rt-modules-core 5.14.0-427.130.1.el9_4, kernel-rt-debug-modules 5.14.0-427.130.1.el9_4, +4 more
    fixed: vendor fix RHSA-2026:25028
  • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt 5.14.0-570.120.1.el9_6, kernel-rt-64k 5.14.0-570.120.1.el9_6, kernel-rt-core 5.14.0-570.120.1.el9_6, kernel-rt-modules 5.14.0-570.120.1.el9_6, kernel-rt-64k-core 5.14.0-570.120.1.el9_6, kernel-rt-debug-core 5.14.0-570.120.1.el9_6, +14 more
    fixed: vendor fix RHSA-2026:25218
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.15.1.el9_8, kernel-rt-core 5.14.0-687.15.1.el9_8, kernel-rt-modules 5.14.0-687.15.1.el9_8, kernel-rt-debug-core 5.14.0-687.15.1.el9_8, kernel-rt-modules-core 5.14.0-687.15.1.el9_8, kernel-rt-debug-modules 5.14.0-687.15.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:25217
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt 5.14.0-427.130.1.el9_4, kernel-rt-kvm 5.14.0-427.130.1.el9_4, kernel-rt-core 5.14.0-427.130.1.el9_4, kernel-rt-modules 5.14.0-427.130.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.130.1.el9_4, kernel-rt-debug-core 5.14.0-427.130.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:25028
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt 5.14.0-570.120.1.el9_6, kernel-rt-kvm 5.14.0-570.120.1.el9_6, kernel-rt-core 5.14.0-570.120.1.el9_6, kernel-rt-modules 5.14.0-570.120.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.120.1.el9_6, kernel-rt-debug-core 5.14.0-570.120.1.el9_6, +6 more
    fixed: vendor fix RHSA-2026:25218
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-26-295-11 updated cvss 7.8

Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.7 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.7
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-26-209-04 updated cvss 7.8

Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.6 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.6
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.10% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.