openvswitch: Fix CT limit teardown use-after-free

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89488
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:19:30 UTC
Updated2026-09-14 13:19:05 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: openvswitch: Fix CT limit teardown use-after-free Packet processing uses CT limit state under RCU, while netns teardown frees that state under ovs_mutex. The CT limit pointer was neither removed from readers nor protected by a grace period, allowing packet processing to dereference the freed state. An unprivileged user can trigger this bug from a user and network namespace, causing a slab-use-after-free in ovs_ct_execute() when the netns is torn down. Publish the CT limit pointer through RCU, remove it before teardown, and wait for readers before freeing its contents. Keep ovs_mutex around individual CT limit updates, and use the RCU read-side lock while GET traverses the RCU-protected limit lists. Netns teardown detaches the RCU-protected CT limit state in the pernet .pre_exit callback while holding ovs_mutex. The pernet core guarantees an RCU grace period between the .pre_exit and .exit callbacks, so the .exit callback completes the teardown without adding any extra synchronization. The netlink command handlers do not need NULL checks because the userspace netlink socket holds an active reference to its network namespace while a request is processed. The per-netns exit path therefore cannot run concurrently with SET, DEL, or GET for that socket's namespace.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001240000 probability, percentile 0.024060000 (date 2026-09-14)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 239f26589a6926db28c436e14f28517581ef1385 git Not specified
CNA Linux Linux affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 3b9369881b403f4cdbb11fa998554382bdcc3d8c git Not specified
CNA Linux Linux affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 3b41d907400cc1dd1da9555b81dca422b1f44433 git Not specified
CNA Linux Linux affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 680f20d5937fa4d1367c59fe83091b78041015f5 git Not specified
CNA Linux Linux affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 bf4aaa7ea2579e24ed7de2e20578a875bebca011 git Not specified
CNA Linux Linux affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 e15407c3a8a005324f633cd46cd8fb58042c1157 git Not specified
CNA Linux Linux affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 6a6d36fadb8537d9b79e72c9fa51885ec0c33e10 git Not specified
CNA Linux Linux affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 403f96c32c9e24600093d7d0c61c17daeedca957 git Not specified
CNA Linux Linux affected 4.18 Not specified
CNA Linux Linux unaffected 4.18 semver Not specified
CNA Linux Linux unaffected 5.10.270 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.221 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.188 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.51 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/3b9369881b403f4cdbb11fa998554382bdcc3d8c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e15407c3a8a005324f633cd46cd8fb58042c1157 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6a6d36fadb8537d9b79e72c9fa51885ec0c33e10 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bf4aaa7ea2579e24ed7de2e20578a875bebca011 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/239f26589a6926db28c436e14f28517581ef1385 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/403f96c32c9e24600093d7d0c61c17daeedca957 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3b41d907400cc1dd1da9555b81dca422b1f44433 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/680f20d5937fa4d1367c59fe83091b78041015f5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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