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CVE-2026-89488— openvswitch: Fix CT limit teardown use-after-free

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，以下漏洞已修复： Open vSwitch：修复连接跟踪（CT）限制清理过程中的释放后使用（use-after-free）问题 漏洞描述： 在数据包处理过程中，连接跟踪（CT）限制状态在 RCU（Read-Copy-Update）保护下被使用，而命名空间（netns）清理时却在 互斥锁保护下释放该状态。由于 CT 限制指针既未从 RCU 读取者（readers）中移除，也未通过宽限期（grace period）进行保护，导致数据包处理代码可能在状态被释放后仍尝试解引用（dereference

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux 11efd5cb04a184eea4f57b68ea63dddd463158d1< e15407c3a8a005324f633cd46cd8fb58042c1157 affected
11efd5cb04a184eea4f57b68ea63dddd463158d1< 6a6d36fadb8537d9b79e72c9fa51885ec0c33e10 affected
11efd5cb04a184eea4f57b68ea63dddd463158d1< 403f96c32c9e24600093d7d0c61c17daeedca957 affected
4.18 affected
< 4.18 unaffected
6.18.51≤ 6.18.* unaffected
7.2.4≤ 7.2.* unaffected
7.3-rc1≤ * unaffected
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I. Basic Information for CVE-2026-89488

Vulnerability Information
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Vulnerability Title
openvswitch: Fix CT limit teardown use-after-free
Source: CVE Program / CVE List V5
Vulnerability Description
In 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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 11efd5cb04a184eea4f57b68ea63dddd463158d1 ~ e15407c3a8a005324f633cd46cd8fb58042c1157 -
Linux Linux 4.18 -

II. Public POCs for CVE-2026-89488

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III. Intelligence Information for CVE-2026-89488

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Other References for CVE-2026-89488 (3)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89490 ocfs2: fix readdir position truncation on 32-bit kernels
CVE-2026-89477 sctp: fix NULL deref on untransmitted RECONF completion
CVE-2026-89478 sctp: drop a chunk if its transport was removed
CVE-2026-89479 sctp: stop processing a packet once its association is deleted
CVE-2026-89480 nvme-tcp: reject a read that transferred too few bytes
CVE-2026-89482 nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89481 nvme-tcp: fix host memory disclosure on R2T for a read command
CVE-2026-89483 nvme: zero the discard fallback page
CVE-2026-89484 lockd: fix NULL dereference on lockowner allocation failure
CVE-2026-89485 lockd: pin next file across nlm_inspect_file lock-drop
CVE-2026-89486 ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
CVE-2026-89487 openvswitch: only skb_tx_error() a packet we are about to drop
CVE-2026-89489 openrisc: fix arbitrary kernel memory access via or1k_atomic syscall
CVE-2026-89491 ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()
CVE-2026-89501 ring-buffer: Hold cpu_buffer::lock when resizing a subbuf
CVE-2026-89498 orangefs: fix double-free of trailer_buf on readdir copy failure
CVE-2026-89499 ring-buffer: Stop remote reader update when page swap fails
CVE-2026-89500 ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page
CVE-2026-89497 orangefs: skip leading spaces before parsing client debug masks
CVE-2026-89502 ring-buffer: Free cpu_buffer::free_page with subbuf_order

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-89488

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