Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13 ip_vs_sched.c ip_vs_bind_scheduler sched null pointer dereference

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Summaryinfo

A vulnerability was found in Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13. It has been rated as critical. This affects the function ip_vs_bind_scheduler of the file net/netfilter/ipvs/ip_vs_sched.c. Performing a manipulation of the argument sched results in null pointer dereference. This vulnerability is reported as CVE-2026-43086. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13. It has been classified as critical. This affects the function ip_vs_bind_scheduler of the file net/netfilter/ipvs/ip_vs_sched.c. The manipulation of the argument sched with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ipvs: fix NULL deref in ip_vs_add_service error path When ip_vs_bind_scheduler() succeeds in ip_vs_add_service(), the local variable sched is set to NULL. If ip_vs_start_estimator() subsequently fails, the out_err cleanup calls ip_vs_unbind_scheduler(svc, sched) with sched == NULL. ip_vs_unbind_scheduler() passes the cur_sched NULL check (because svc->scheduler was set by the successful bind) but then dereferences the NULL sched parameter at sched->done_service, causing a kernel panic at offset 0x30 from NULL. Oops: general protection fault, [..] [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] RIP: 0010:ip_vs_unbind_scheduler (net/netfilter/ipvs/ip_vs_sched.c:69) Call Trace: <TASK> ip_vs_add_service.isra.0 (net/netfilter/ipvs/ip_vs_ctl.c:1500) do_ip_vs_set_ctl (net/netfilter/ipvs/ip_vs_ctl.c:2809) nf_setsockopt (net/netfilter/nf_sockopt.c:102) [..] Fix by simply not clearing the local sched variable after a successful bind. ip_vs_unbind_scheduler() already detects whether a scheduler is installed via svc->scheduler, and keeping sched non-NULL ensures the error path passes the correct pointer to both ip_vs_unbind_scheduler() and ip_vs_scheduler_put(). While the bug is older, the problem popups in more recent kernels (6.2), when the new error path is taken after the ip_vs_start_estimator() call.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-43086 since 05/01/2026. The exploitability is told to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 329305 (openSUSE 16: cluster-md-kmp-64kb / cluster-md-kmp-azure / cluster-md-kmp-default / etc (openSUSE-SU-2026:21388-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.136, 6.12.83, 6.18.24 or 6.19.14 eliminates this vulnerability. Applying the patch 730663352c9178f33fcf5929f4a37c1f1ca5a693/4039959315008888dd53c37674d33351817a5166/a32dabacee111cea083ddd57a03635672e1bff29/c2ddbe577e2ebf63f2d8fb15cdc7503af70f3e94/9a91797e61d286805ae10a92cc48959c30800556 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 databases at Tenable (329305) and CERT Bund (WID-SEC-2026-1385). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Microsoft Azure Linux

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 329305
Nessus Name: openSUSE 16: cluster-md-kmp-64kb / cluster-md-kmp-azure / cluster-md-kmp-default / etc (openSUSE-SU-2026:21388-1)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.136/6.12.83/6.18.24/6.19.14
Patch: 730663352c9178f33fcf5929f4a37c1f1ca5a693/4039959315008888dd53c37674d33351817a5166/a32dabacee111cea083ddd57a03635672e1bff29/c2ddbe577e2ebf63f2d8fb15cdc7503af70f3e94/9a91797e61d286805ae10a92cc48959c30800556

Timelineinfo

05/01/2026 CVE reserved
05/06/2026 +5 days Advisory disclosed
05/06/2026 +0 days VulDB entry created
07/25/2026 +80 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43086 (🔒)
GCVE (CVE): GCVE-0-2026-43086
GCVE (VulDB): GCVE-100-361347
CERT Bund: WID-SEC-2026-1385 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 05/06/2026 12:57
Updated: 07/25/2026 08:25
Changes: 05/06/2026 12:57 (60), 05/07/2026 04:28 (7), 06/04/2026 11:08 (12), 06/08/2026 16:19 (1), 07/25/2026 08:25 (4)
Complete: 🔍
Cache ID: 216::103

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