Linux Kernel up to 6.12.112/6.18.55/7.2.9/7.3-rc5 io_uring io_req_normal_work_add use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k1.37-

Summaryinfo

A vulnerability classified as very critical was found in Linux Kernel up to 6.12.112/6.18.55/7.2.9/7.3-rc5. This issue affects the function io_req_normal_work_add of the component io_uring. Executing a manipulation can lead to use after free. This vulnerability is handled as CVE-2026-98858. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as very critical was found in Linux Kernel up to 6.12.112/6.18.55/7.2.9/7.3-rc5. This vulnerability affects the function io_req_normal_work_add of the component io_uring. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-98858 since 09/25/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 10/18/2026).

Upgrading to version 6.12.113, 6.18.56, 7.2.10 or 7.3-rc6 eliminates this vulnerability. Applying the patch 42b3332efacfd2140be4cd0dedad4fb96b8ae90e/891bd8335a0de3bb15c3b797ce3026bbb0dbef6c/395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3/a92193c91e8839fe5fc209616ea95465ae4b919d is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-103798). Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.113/6.18.56/7.2.10/7.3-rc6
Patch: 42b3332efacfd2140be4cd0dedad4fb96b8ae90e/891bd8335a0de3bb15c3b797ce3026bbb0dbef6c/395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3/a92193c91e8839fe5fc209616ea95465ae4b919d

Timelineinfo

09/25/2026 CVE reserved
10/18/2026 +23 days Advisory disclosed
10/18/2026 +0 days VulDB entry created
10/18/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98858 (🔒)
GCVE (CVE): GCVE-0-2026-98858
GCVE (VulDB): GCVE-100-421876
EUVD: 🔒

Entryinfo

Created: 10/18/2026 18:43
Updated: 10/18/2026 19:50
Changes: 10/18/2026 18:43 (59), 10/18/2026 19:50 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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