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CriticalFix available

NFSv4: remove callback IDR entry on client allocation failure

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: NFSv4: remove callback IDR entry on client allocation failure nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it finishes setting up the client. If any later initialization step fails, the error path frees the nfs_client directly with nfs_free_client(). That bypasses nfs_put_client(), which is where the callback IDR entry is removed during normal teardown. A failed allocation can therefore leave cb_ident_idr pointing at a freed nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the stale pointer and take a reference to it. Make the callback IDR removal helper callable by the allocation failure path, and remove the callback identifier before freeing the client. This was found by a local static-analysis checker for publish-before-free lifetime bugs and confirmed by manual inspection.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.270, 5.15.221, 6.1.188, 6.12.110, 6.18.52, 6.6.157, 7.2.6
CVEs
CVE-2026-90151
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 17:38 UTC · Revision 1

Source evidence

NFSv4: remove callback IDR entry on client allocation failure

core-osv · Original source

Published 17 Sept 2026, 16:06 UTC

In the Linux kernel, the following vulnerability has been resolved: NFSv4: remove callback IDR entry on client allocation failure nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it finishes setting up the client. If any later initialization step fails, the error path frees the nfs_client directly with nfs_free_client(). That bypasses nfs_put_client(), which is where the callback IDR entry is removed during normal teardown. A failed allocation can therefore leave cb_ident_idr pointing at a freed nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the stale pointer and take a reference to it. Make the callback IDR removal helper callable by the allocation failure path, and remove the callback identifier before freeing the client. This was found by a local static-analysis checker for publish-before-free lifetime bugs and confirmed by manual inspection.

osv:CVE-2026-90151

Kernel

Fixed versions: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6

Complete source record
{
  "id": "832509d038086a600f6f1d29ece0c9c9d2a6a9f5e184c7506f05bbeb5a3f26a1",
  "url": "https://osv.dev/vulnerability/CVE-2026-90151",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "NFSv4: remove callback IDR entry on client allocation failure",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: NFSv4: remove callback IDR entry on client allocation failure nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it finishes setting up the client. If any later initialization step fails, the error path frees the nfs_client directly with nfs_free_client(). That bypasses nfs_put_client(), which is where the callback IDR entry is removed during normal teardown. A failed allocation can therefore leave cb_ident_idr pointing at a freed nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the stale pointer and take a reference to it. Make the callback IDR removal helper callable by the allocation failure path, and remove the callback identifier before freeing the client. This was found by a local static-analysis checker for publish-before-free lifetime bugs and confirmed by manual inspection.",
    "evidence": "osv:CVE-2026-90151",
    "products": [
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          "evidence": "/affected/1/package/name"
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        "prerequisites": [],
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            "evidence": "/affected/1/ranges"
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        "affected_versions": []
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    "severity": "critical",
    "structured": {
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      "aliases": [
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      "metrics": [
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          "type": "CVSS_V3",
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
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      "modified": "2026-10-28T02:30:37.860852538Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/3f2387e8bfbc4efda5d77c3a11a028d0a119c48f",
        "https://git.kernel.org/stable/c/5891c03e150920618db0e9c4ea2d772abacdcfd1",
        "https://git.kernel.org/stable/c/68c721391b761dbe38d5b0094d2bb6e8489ad92b",
        "https://git.kernel.org/stable/c/7c4812eb96bdcafb31a65b12f2aa96659429d1d4",
        "https://git.kernel.org/stable/c/80b1c3d5a881f7d9081aa9f46da9742878a0f893",
        "https://git.kernel.org/stable/c/9bfdd0f591307b5198826a0e7a5b2f35f87acd2d",
        "https://git.kernel.org/stable/c/d05c2007b3d84ccba11dc6e9cb3202768cc72f14",
        "https://git.kernel.org/stable/c/fc95ca82d5ae598c428ab5a00ae69f8526d59371",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90151.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90151",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90151.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90151",
        "evidence": "/id"
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    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505371,
  "published_at": "2026-09-17T16:06:44.987+00:00"
}