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CVE-2026-98441— net/sched: act_ct: avoid modifying shared unconfirmed ct entry

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，以下漏洞已被修复： net/sched: act_ct：避免修改共享的未确认连接跟踪（ct）条目 当携带未确认连接跟踪条目的 skb（套接字缓冲区）被克隆时，我们可能会再次处理这两个克隆包，但此时它们携带的扩展集合不同。 事件序列如下： 1. 第一个克隆包尝试提交（commit），并运行辅助函数（helpers），将扩展指针写入期望列表（expectation list）。 2. 随后，该克隆包未能完成确认，导致条目仍处于未确认状态。 3. 第二个克隆包随后尝试提交标签或执行 NAT，并为此

CVSS 7.8 · High EPSS 0.13% · P3

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux a21b06e7319129994f339ed47f512bbe57b77f5b< c812bb4aea13d385d048b5b24756aee2edf6f99e affected
a21b06e7319129994f339ed47f512bbe57b77f5b< 2b783c562c3238ff50c34fd7a72a735c9cc73d9a affected
a21b06e7319129994f339ed47f512bbe57b77f5b< 4a04ed91575819fb1859311113e95700b709bec7 affected
a21b06e7319129994f339ed47f512bbe57b77f5b< b097d9d7a5b09c8ec5c4c1a08e35ac5a66b06b44 affected
a21b06e7319129994f339ed47f512bbe57b77f5b< f85009dfcd65e5969526b0db7a49b5413746e630 affected
6.2 affected
< 6.2 unaffected
6.6.160≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-98441

Vulnerability Information
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Vulnerability Title
net/sched: act_ct: avoid modifying shared unconfirmed ct entry
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: avoid modifying shared unconfirmed ct entry In a case where skb with an unconfirmed ct entry gets cloned, we may end up processing both again but with different sets of extensions. The series of events: 1. The first clone wants to commit and runs the helpers wiring up the extension pointer into the expectation list. 2. Then it looses the confirmation keeping the entry unconfirmed. 3. Second clone now wants to commit labels or run NAT and adds the new extension for that breaking the pointer in the expectation list causing UAF on the destruction path later. While this is possible to trigger, there should be no practical network pipeline where we need to process both clones without modifications in the same zone. So, let's just reset the entry in case for some reason we got an skb with a shared one. This doesn't affect any known use cases, but avoids any potential problems with sharing and modification of the unconfirmed ct entry. Unlike openvswitch module, act_ct allows for NAT without commit. Changing that would be a uAPI break. So, act_ct needs to reset on NAT regardless of the commit flag to avoid reallocation of the extension space. This, however, doesn't really change the picture for sensible networking cases as there should be no need to run the same packet twice (before and after the clone) through conntrack without packet header or zone changes and without commit. The fixes tag points to the introduction of helpers, since that's the main UAF trigger for the sharing.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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 a21b06e7319129994f339ed47f512bbe57b77f5b ~ c812bb4aea13d385d048b5b24756aee2edf6f99e -
Linux Linux 6.2 -

II. Public POCs for CVE-2026-98441

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III. Intelligence Information for CVE-2026-98441

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Patches & Fixes for CVE-2026-98441 (5)

Same Patch Batch · Linux · 2026-10-18 · 435 CVEs total

CVE-2026-98548 9.8 CRITICAL sctp: discard the rest of the packet on a stale-cookie error
CVE-2026-98490 9.8 CRITICAL net: openvswitch: conntrack: fix helper UAF due to extensions realloc
CVE-2026-98464 9.3 CRITICAL RISC-V: KVM: Synchronize hrtimer callback during teardown
CVE-2026-98549 9.1 CRITICAL tcp: prevent collapsing skbs across boundary in rtx queue
CVE-2026-98451 8.8 HIGH smb: client: use finish_no_open() for non-regular inodes
CVE-2026-98466 8.2 HIGH KVM: arm64: Transfer the hyp stack pages out of the host stage-2
CVE-2026-98532 8.1 HIGH ipv6: do not let ipv6_find_hdr() return an offset past the packet end
CVE-2026-98499 8.1 HIGH HID: wacom: fix OOB read in wacom_wac_pen_serial_enforce()
CVE-2026-98454 8.1 HIGH smb: client: fix create context out-of-bounds reads
CVE-2026-98524 7.8 HIGH rds: ib: Clear the sg list when mapping an MR fails
CVE-2026-98520 7.8 HIGH drm/amdkfd: fix use-after-free and multi-container gap in kfd_dev_mapping
CVE-2026-98491 7.8 HIGH net: openvswitch: conntrack: avoid modifying shared unconfirmed ct entry
CVE-2026-98507 7.8 HIGH mm/rmap: fix missing barrier between anon_vma init and vma->anon_vma publish
CVE-2026-98436 7.8 HIGH accel/amdxdna: Disable device buffer exporting
CVE-2026-98510 7.8 HIGH drm/xe/vm: nuke PTs only after unlinking contested VMAs
CVE-2026-98515 7.8 HIGH drm/nouveau: fix double-free in nvif_vmm_dtor
CVE-2026-98487 7.8 HIGH net: bridge: mdb: restart port group walk after deletion
CVE-2026-98517 7.8 HIGH drm/nouveau/uvmm: fix UAF in nouveau_uvmm_sm when BO is in TTM_PL_SYSTEM
CVE-2026-98443 7.8 HIGH xfs: fix cursor and pointer handling when recovering iunlink buckets
CVE-2026-98442 7.8 HIGH net/sched: act_ct: fix helper UAF due to extensions realloc

Showing top 20 of 435 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

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Same vendor: Linux