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CVE-2026-98858— io_uring: fix task_work add use-after-free with SQPOLL

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，以下漏洞已得到修复： io_uring：修复 SQPOLL 模式下 task_work 添加时的释放后使用（use-after-free）问题 对于 SQPOLL 模式，sqpoll 线程会从自己的列表中执行 task_work，因此无需额外通知它；一旦 发布请求，该线程即可立即弹出并完成该请求。如果该请求是维持 ring 存活的最后一个请求， 便会释放 ctx、停止线程及其关联的 tctx。然而，此时 在 操作之后仍在访问这两个对象，从而引发以下错误： 修复方案：在添加操作期间持有 RCU

AI Predicted 7.8 Difficulty: Moderate

Possible ATT&CK Techniques 1 AI

T1069.005

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux af5d68f8892f8ee8f137648b79ceb2abc153a19b< 42b3332efacfd2140be4cd0dedad4fb96b8ae90e affected
af5d68f8892f8ee8f137648b79ceb2abc153a19b< 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c affected
af5d68f8892f8ee8f137648b79ceb2abc153a19b< 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3 affected
af5d68f8892f8ee8f137648b79ceb2abc153a19b< a92193c91e8839fe5fc209616ea95465ae4b919d affected
6.9 affected
< 6.9 unaffected
6.12.113≤ 6.12.* unaffected
6.18.56≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-98858

Vulnerability Information
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Vulnerability Title
io_uring: fix task_work add use-after-free with SQPOLL
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: io_uring: fix task_work add use-after-free with SQPOLL For SQPOLL, the sqpoll thread runs task_work off its own list and doesn't need to be told about it, so it can pop and complete a request as soon as mpscq_push() has published it. If that was the last request holding the ring alive, io_ring_exit_work() then frees the ctx, stops the thread, and with it the tctx, while io_req_normal_work_add() is still looking at both after the push: BUG: KASAN: slab-use-after-free in io_req_normal_work_add+0x439/0x510 Read of size 4 at addr ff11000000ca0000 by task repro/55 (...) BUG: KASAN: slab-use-after-free in queue_work_on+0x25/0x70 Write of size 8 at addr ff11000000c3bd00 by task repro/55 Hold an RCU read lock across the add, like io_req_local_work_add() already does, and have io_ring_exit_work() wait for a grace period for SQPOLL rings as well before freeing the ctx.
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 af5d68f8892f8ee8f137648b79ceb2abc153a19b ~ 42b3332efacfd2140be4cd0dedad4fb96b8ae90e -
Linux Linux 6.9 -

II. Public POCs for CVE-2026-98858

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III. Intelligence Information for CVE-2026-98858

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Patches & Fixes for CVE-2026-98858 (4)

Same Patch Batch · Linux · 2026-10-18 · 436 CVEs total

CVE-2026-98582 nfc: st21nfca: validate received frame size
CVE-2026-98568 vxlan: use one headroom snapshot for neighbour replies
CVE-2026-98570 net: ipv6: keep room for the mac header in dst_dev_overhead()
CVE-2026-98571 net: stmmac: clear stale buf->page after recycling on skb build failure
CVE-2026-98572 bpf: Fix immediate JMP JEQ/JNE on MIPS32
CVE-2026-98573 net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()
CVE-2026-98574 net: bcmgenet: stop Tx NAPI before disabling the queues
CVE-2026-98575 nfc: pn533: fix OOB read in pn533_acr122_is_rx_frame_valid()
CVE-2026-98576 nfc: llcp: fix slab-out-of-bounds reads when logging service names
CVE-2026-98577 nfc: llcp: fix WKS SAP hijacking via prefix match in nfc_llcp_wks_sap()
CVE-2026-98578 nfc: st21nfca: validate ISO15693 inventory length
CVE-2026-98579 nfc: llcp: fix sdreq TLV list leak on parse/alloc/send failure
CVE-2026-98580 nfc: llcp: Fix race condition in accept_queue lifecycle
CVE-2026-98581 nfc: llcp: Fix list corruption / refcount desync in nfc_llcp_recv_dm()
CVE-2026-98593 s390/debug: Fix NULL pointer dereference in debug_info_copy()
CVE-2026-98590 bpf: Fix bpf_sock context code generation
CVE-2026-98591 bpf: Fix bounds check for skb-backed dynptrs
CVE-2026-98592 net: spacemit: clear TX descriptor on fragment mapping failure
CVE-2026-98589 bpf: Reject pkt arguments in mutating subprogs
CVE-2026-98594 tg3: clean up PHYLIB resources on probe failure

Showing top 20 of 436 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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