GHSA-HG4P-7H98-9FMH
Vulnerability from github – Published: 2026-05-06 12:30 – Updated: 2026-06-01 18:31In 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: 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.
{
"affected": [],
"aliases": [
"CVE-2026-43086"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-06T10:16:21Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: fix NULL deref in ip_vs_add_service error path\n\nWhen ip_vs_bind_scheduler() succeeds in ip_vs_add_service(), the local\nvariable sched is set to NULL. If ip_vs_start_estimator() subsequently\nfails, the out_err cleanup calls ip_vs_unbind_scheduler(svc, sched)\nwith sched == NULL. ip_vs_unbind_scheduler() passes the cur_sched NULL\ncheck (because svc-\u003escheduler was set by the successful bind) but then\ndereferences the NULL sched parameter at sched-\u003edone_service, causing a\nkernel panic at offset 0x30 from NULL.\n\n Oops: general protection fault, [..] [#1] PREEMPT SMP KASAN NOPTI\n KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]\n RIP: 0010:ip_vs_unbind_scheduler (net/netfilter/ipvs/ip_vs_sched.c:69)\n Call Trace:\n \u003cTASK\u003e\n ip_vs_add_service.isra.0 (net/netfilter/ipvs/ip_vs_ctl.c:1500)\n do_ip_vs_set_ctl (net/netfilter/ipvs/ip_vs_ctl.c:2809)\n nf_setsockopt (net/netfilter/nf_sockopt.c:102)\n [..]\n\nFix by simply not clearing the local sched variable after a successful\nbind. ip_vs_unbind_scheduler() already detects whether a scheduler is\ninstalled via svc-\u003escheduler, and keeping sched non-NULL ensures the\nerror path passes the correct pointer to both ip_vs_unbind_scheduler()\nand ip_vs_scheduler_put().\n\nWhile the bug is older, the problem popups in more recent kernels (6.2),\nwhen the new error path is taken after the ip_vs_start_estimator() call.",
"id": "GHSA-hg4p-7h98-9fmh",
"modified": "2026-06-01T18:31:29Z",
"published": "2026-05-06T12:30:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43086"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4039959315008888dd53c37674d33351817a5166"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/730663352c9178f33fcf5929f4a37c1f1ca5a693"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9a91797e61d286805ae10a92cc48959c30800556"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a32dabacee111cea083ddd57a03635672e1bff29"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c2ddbe577e2ebf63f2d8fb15cdc7503af70f3e94"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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