Vulnerability-Lookup

GHSA-F8R4-W3WX-2XX3

Vulnerability from github – Published: 2026-09-17 18:31 – Updated: 2026-09-18 18:31

Details

In the Linux kernel, the following vulnerability has been resolved:

net: kcm: Hold RCU read lock while running BPF parser

kcm_parse_func_strparser() calls bpf_prog_run_pin_on_cpu() which prevents CPU migration, but does not establish an RCU read-side critical section. Consequently, BPF map operations can trigger WARN_ON_ONCE(!bpf_rcu_lock_held()) when called from the KCM strparser program.

Hold the RCU read lock while running the program.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-90143"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-17T17:17:07Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: kcm: Hold RCU read lock while running BPF parser\n\nkcm_parse_func_strparser() calls bpf_prog_run_pin_on_cpu() which\nprevents CPU migration, but does not establish an RCU read-side\ncritical section. Consequently, BPF map operations can trigger\nWARN_ON_ONCE(!bpf_rcu_lock_held()) when called from the KCM strparser\nprogram.\n\nHold the RCU read lock while running the program.",
  "id": "GHSA-f8r4-w3wx-2xx3",
  "modified": "2026-09-18T18:31:27Z",
  "published": "2026-09-17T18:31:52Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90143"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1d26a6e007d46babc7fa76e5a157dccf86cd55c0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/21526f8a191a3c50622b8c10bd927870d780eae4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/292846223eaddba890e40699d2ab82ee5671798c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/37108861cf7bd909d4a372069bcd61c8f489e232"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3c70d27e792a28bca650ddd8a9aa0fe3591ffec5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b0346dd64e4905291cc9c479f2e6cf1884ced4e6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b0e94ea63dbdcbfec9beb819cd5f8fa584809ef2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f392affef3c9ce64dfdde794df0579e0a7793440"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-90143 (GCVE-0-2026-90143)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:06 – Updated: 2026-09-18 17:53

Title

net: kcm: Hold RCU read lock while running BPF parser

Summary

In the Linux kernel, the following vulnerability has been resolved: net: kcm: Hold RCU read lock while running BPF parser kcm_parse_func_strparser() calls bpf_prog_run_pin_on_cpu() which prevents CPU migration, but does not establish an RCU read-side critical section. Consequently, BPF map operations can trigger WARN_ON_ONCE(!bpf_rcu_lock_held()) when called from the KCM strparser program. Hold the RCU read lock while running the program.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/37108861cf7bd909d…
https://git.kernel.org/stable/c/3c70d27e792a28bca…
https://git.kernel.org/stable/c/1d26a6e007d46babc…
https://git.kernel.org/stable/c/b0e94ea63dbdcbfec…
https://git.kernel.org/stable/c/21526f8a191a3c506…
https://git.kernel.org/stable/c/292846223eaddba89…
https://git.kernel.org/stable/c/f392affef3c9ce64d…
https://git.kernel.org/stable/c/b0346dd64e4905291…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9b73896a81dc68a638a011877b7344b252f92276 , < 37108861cf7bd909d4a372069bcd61c8f489e232 (git) Affected: 9b73896a81dc68a638a011877b7344b252f92276 , < 3c70d27e792a28bca650ddd8a9aa0fe3591ffec5 (git) Affected: 9b73896a81dc68a638a011877b7344b252f92276 , < 1d26a6e007d46babc7fa76e5a157dccf86cd55c0 (git) Affected: 9b73896a81dc68a638a011877b7344b252f92276 , < b0e94ea63dbdcbfec9beb819cd5f8fa584809ef2 (git) Affected: 9b73896a81dc68a638a011877b7344b252f92276 , < 21526f8a191a3c50622b8c10bd927870d780eae4 (git) Affected: 9b73896a81dc68a638a011877b7344b252f92276 , < 292846223eaddba890e40699d2ab82ee5671798c (git) Affected: 9b73896a81dc68a638a011877b7344b252f92276 , < f392affef3c9ce64dfdde794df0579e0a7793440 (git) Affected: 9b73896a81dc68a638a011877b7344b252f92276 , < b0346dd64e4905291cc9c479f2e6cf1884ced4e6 (git)
Linux	Linux	Affected: 4.9 Unaffected: 0 , < 4.9 (semver) Unaffected: 5.10.270 , ≤ 5.10.* (semver) Unaffected: 5.15.221 , ≤ 5.15.* (semver) Unaffected: 6.1.188 , ≤ 6.1.* (semver) Unaffected: 6.6.157 , ≤ 6.6.* (semver) Unaffected: 6.12.110 , ≤ 6.12.* (semver) Unaffected: 6.18.52 , ≤ 6.18.* (semver) Unaffected: 7.2.6 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/kcm/kcmsock.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "9b73896a81dc68a638a011877b7344b252f92276",
              "versionType": "git"
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              "versionType": "git"
            },
            {
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              "versionType": "git"
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              "versionType": "git"
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              "versionType": "git"
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              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
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              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
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              "versionType": "semver"
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
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        }
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: kcm: Hold RCU read lock while running BPF parser\n\nkcm_parse_func_strparser() calls bpf_prog_run_pin_on_cpu() which\nprevents CPU migration, but does not establish an RCU read-side\ncritical section. Consequently, BPF map operations can trigger\nWARN_ON_ONCE(!bpf_rcu_lock_held()) when called from the KCM strparser\nprogram.\n\nHold the RCU read lock while running the program."
        }
      ],
      "metrics": [
        {
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
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              "lang": "en",
              "value": "AV:L - The missing rcu_read_lock is in kcm_parse_func_strparser(), reached after local socket(AF_KCM) and ioctl(SIOCKCMATTACH) installing the caller\u0027s BPF_PROG_TYPE_SOCKET_FILTER via bpf_prog_get_type(). A remote TCP peer can only feed an skb into strp_recv(); map helpers fire regardless of payload, and the BPF program is locally supplied.\nAC:L - kcm_attach() always calls strp_check_rcv(), which queues do_strp_work so parse_msg runs in process context under lock_sock() with BH enabled, so bpf_rcu_lock_held() is false. The attacker loads a SOCKET_FILTER that calls bpf_map_lookup_elem and can delete the same HASH key from their own map fd on another thread.\nPR:L - kcm_create() and kcm_ioctl(SIOCKCMATTACH) have no capable() check, and PF_KCM autoloads via MODULE_ALIAS_NETPROTO. bpf_prog_get_type(..., BPF_PROG_TYPE_SOCKET_FILTER) and HASH/ARRAY maps are the unprivileged types in bpf_prog_load()/map_create(); CAP_BPF in the init namespace is not required when unprivileged BPF is enabled.\nUI:N - The attacker opens their own AF_KCM and TCP sockets, loads their own SOCKET_FILTER, issues SIOCKCMATTACH, and either pre-queues TCP data so strp_check_rcv() runs the parser or writes the TCP peer themselves. No other user must mount a filesystem, open a device, or attach a program.\nS:U - A dangling htab_elem used by kcm_parse_func_strparser() is a host-kernel use-after-free that can escalate privileges inside the same kernel. It does not cross a KVM/Xen guest-host boundary or an IOMMU/DMA domain.\nC:H - bpf_map_lookup_elem() proceeds after WARN_ON_ONCE(!bpf_rcu_lock_held()) and __htab_map_lookup_elem() still returns a pointer. Concurrent htab delete via the attacker\u0027s map fd frees or freelist-reuses that htab_elem (bpf_mem_cache_free/pcpu_freelist_push) while the SOCKET_FILTER still reads the map value, disclosing kernel heap.\nI:H - The verifier treats the map-value pointer as writable, so the SOCKET_FILTER can store through the dangling htab_elem after free_htab_elem() reuses it, and bpf_map_update_elem() also runs without RCU from kcm_parse_func_strparser(). That is an arbitrary kernel write via heap reuse, not a bounded overwrite.\nA:H - Use of the dangling htab_elem in do_strp_work oopses or panics the kernel. Independently, bpf_map_lookup_elem()/__htab_map_lookup_elem() hit WARN_ON_ONCE(!bpf_rcu_lock_held()) on the first map helper from kcm_parse_func_strparser(), which is fatal on kernels booted with panic_on_warn."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-18T17:53:21.163Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/b0e94ea63dbdcbfec9beb819cd5f8fa584809ef2"
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        {
          "url": "https://git.kernel.org/stable/c/b0346dd64e4905291cc9c479f2e6cf1884ced4e6"
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      "title": "net: kcm: Hold RCU read lock while running BPF parser",
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90143",
    "datePublished": "2026-09-17T16:06:39.775Z",
    "dateReserved": "2026-09-11T19:38:34.789Z",
    "dateUpdated": "2026-09-18T17:53:21.163Z",
    "state": "PUBLISHED"
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  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-F8R4-W3WX-2XX3

CVE-2026-90143 (GCVE-0-2026-90143)

Tags

Sightings

Nomenclature

Related by attack behaviour