Linux Kernel up to 6.19.5 tcf_skbedit_hash divide by zero

CVSS Meta Temp Score
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.164/6.6.127/6.12.74/6.18.15/6.19.5. It has been rated as critical. Affected by this issue is the function tcf_skbedit_hash. This manipulation causes divide by zero. This vulnerability is tracked as CVE-2026-43238. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.1.164/6.6.127/6.12.74/6.18.15/6.19.5 and classified as critical. Affected by this vulnerability is the function tcf_skbedit_hash. The manipulation with an unknown input leads to a divide by zero vulnerability. The CWE definition for the vulnerability is CWE-369. The product divides a value by zero. As an impact it is known to affect availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash() Commit 38a6f0865796 ("net: sched: support hash selecting tx queue") added SKBEDIT_F_TXQ_SKBHASH support. The inclusive range size is computed as: mapping_mod = queue_mapping_max - queue_mapping + 1; The range size can be 65536 when the requested range covers all possible u16 queue IDs (e.g. queue_mapping=0 and queue_mapping_max=U16_MAX). That value cannot be represented in a u16 and previously wrapped to 0, so tcf_skbedit_hash() could trigger a divide-by-zero: queue_mapping += skb_get_hash(skb) % params->mapping_mod; Compute mapping_mod in a wider type and reject ranges larger than U16_MAX to prevent params->mapping_mod from becoming 0 and avoid the crash.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-43238 since 05/01/2026. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 318589 (Oracle Linux 10 / 9 : Unbreakable Enterprise kernel (ELSA-2026-50293)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.165, 6.6.128, 6.12.75, 6.18.16 or 6.19.6 eliminates this vulnerability. Applying the patch 59809fda4da7730cfe84a948033f47eb45db073d/9c735a7d98c982a786b0db71eb6566ee00aaa04f/015cebdfcb97b5347fb7f598ea712a281cb35840/4ece5eb4836f8ff03b9004dc2430a7169f282851/3c2b95b26860bd6f8e2310d31ea1200d3f8f173e/be054cc66f739a9ba615dba9012a07fab8e7dd6f is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (318589). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Divide by zero
CWE: CWE-369 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 318589
Nessus Name: Oracle Linux 10 / 9 : Unbreakable Enterprise kernel (ELSA-2026-50293)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.165/6.6.128/6.12.75/6.18.16/6.19.6
Patch: 59809fda4da7730cfe84a948033f47eb45db073d/9c735a7d98c982a786b0db71eb6566ee00aaa04f/015cebdfcb97b5347fb7f598ea712a281cb35840/4ece5eb4836f8ff03b9004dc2430a7169f282851/3c2b95b26860bd6f8e2310d31ea1200d3f8f173e/be054cc66f739a9ba615dba9012a07fab8e7dd6f

Timelineinfo

05/01/2026 CVE reserved
05/06/2026 +5 days Advisory disclosed
05/06/2026 +0 days VulDB entry created
06/04/2026 +29 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43238 (🔒)
GCVE (CVE): GCVE-0-2026-43238
GCVE (VulDB): GCVE-100-361417

Entryinfo

Created: 05/06/2026 16:35
Updated: 06/04/2026 13:04
Changes: 05/06/2026 16:35 (58), 06/04/2026 13:04 (2)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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