Vulnerability-Lookup

GHSA-2XHX-G2J2-V5CP

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

Details

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

bpf: Reject load-acquire from pointers requiring fault protection

A BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier, unlike a regular BPF_LDX, so the JIT emits a plain load with no exception table entry and a fault panics the kernel instead of being handled.

Reject the source pointer types that a BPF_LDX would have had that fault protection applied to, i.e. the ones bpf_convert_ctx_accesses() turns into BPF_PROBE_MEM: a bare PTR_TO_BTF_ID, PTR_TO_BTF_ID | PTR_UNTRUSTED, PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED and PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED.

This is reachable e.g. by loading ->mm out of a trusted task_struct yields an untrusted pointer to mm_struct, and it is NULL for a kernel thread:

[...] SEC("tp_btf/sched_switch") int BPF_PROG(demo, bool preempt, struct task_struct prev, struct task_struct next) { struct mm_struct mm = next->mm; / untrusted */

  out_ldx = (__u64)mm->pgd;         /* BPF_LDX      */
  out_acq = load_acquire(&mm->pgd); /* BPF_LOAD_ACQ */
  return 0;

} [...]

Both dereference the same pointer, but only the BPF_LDX is protected (x86-64 JIT, jump targets shown prog-relative):

[...] ; out_ldx = (__u64)mm->pgd; 17: movq $-10485760, %r10 1e: movq %rsi, %r11 21: addq $184, %r11 28: subq %r10, %r11 2b: movabsq $140737498841088, %r10 35: cmpq %r10, %r11 38: ja 0x3e <-- kernel addr? 3a: xorl %edi, %edi <-- no: dst = 0, skip the load 3c: jmp 0x45 3e: movq 184(%rsi), %rdi <-- yes: load + extable entry [...] ; load_acquire(&mm->pgd) 53: movq %rsi, %rdi 56: movq 184(%rdi), %rax <-- no check, no extable entry [...]

Note that BPF_PROBE_MEM is not visible in a bpftool xlated dump, as bpf_insn_prepare_dump() rewrites it back to BPF_MEM.

A PTR_TRUSTED pointer is deliberately not on the list. Such a load is not converted either, but it does not need to be, since the pointer is guaranteed live, so load-acquire from it stays allowed.

The check is gated on BPF_LOAD_ACQ so that atomic RMW and store-release error messages are unchanged; writes (RMW / store-release) to such pointers are already rejected elsewhere, so only load-acquire needs this.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-90269"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-17T17:17:23Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject load-acquire from pointers requiring fault protection\n\nA BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier,\nunlike a regular BPF_LDX, so the JIT emits a plain load with no exception\ntable entry and a fault panics the kernel instead of being handled.\n\nReject the source pointer types that a BPF_LDX would have had that fault\nprotection applied to, i.e. the ones bpf_convert_ctx_accesses() turns\ninto BPF_PROBE_MEM: a bare PTR_TO_BTF_ID, PTR_TO_BTF_ID | PTR_UNTRUSTED,\nPTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED and PTR_TO_MEM | MEM_RDONLY |\nPTR_UNTRUSTED.\n\nThis is reachable e.g. by loading -\u003emm out of a trusted task_struct\nyields an untrusted pointer to mm_struct, and it is NULL for a kernel\nthread:\n\n  [...]\n  SEC(\"tp_btf/sched_switch\")\n  int BPF_PROG(demo, bool preempt, struct task_struct *prev,\n               struct task_struct *next)\n  {\n      struct mm_struct *mm = next-\u003emm;  /* untrusted */\n\n      out_ldx = (__u64)mm-\u003epgd;         /* BPF_LDX      */\n      out_acq = load_acquire(\u0026mm-\u003epgd); /* BPF_LOAD_ACQ */\n      return 0;\n  }\n  [...]\n\nBoth dereference the same pointer, but only the BPF_LDX is protected\n(x86-64 JIT, jump targets shown prog-relative):\n\n  [...]\n  ; out_ldx = (__u64)mm-\u003epgd;\n  17:   movq    $-10485760, %r10\n  1e:   movq    %rsi, %r11\n  21:   addq    $184, %r11\n  28:   subq    %r10, %r11\n  2b:   movabsq $140737498841088, %r10\n  35:   cmpq    %r10, %r11\n  38:   ja      0x3e                 \u003c-- kernel addr?\n  3a:   xorl    %edi, %edi           \u003c-- no: dst = 0, skip the load\n  3c:   jmp     0x45\n  3e:   movq    184(%rsi), %rdi      \u003c-- yes: load + extable entry\n  [...]\n  ; load_acquire(\u0026mm-\u003epgd)\n  53:\tmovq    %rsi, %rdi\n  56:\tmovq    184(%rdi), %rax       \u003c-- no check, no extable entry\n  [...]\n\nNote that BPF_PROBE_MEM is not visible in a bpftool xlated dump, as\nbpf_insn_prepare_dump() rewrites it back to BPF_MEM.\n\nA PTR_TRUSTED pointer is deliberately not on the list. Such a load is\nnot converted either, but it does not need to be, since the pointer is\nguaranteed live, so load-acquire from it stays allowed.\n\nThe check is gated on BPF_LOAD_ACQ so that atomic RMW and store-release\nerror messages are unchanged; writes (RMW / store-release) to such\npointers are already rejected elsewhere, so only load-acquire needs this.",
  "id": "GHSA-2xhx-g2j2-v5cp",
  "modified": "2026-09-17T18:31:58Z",
  "published": "2026-09-17T18:31:58Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90269"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5f8ade6e9b7931fc9697394f1b2c4ae833f5ac18"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7db0a00445f1a40bacfe9b747405c11cb5f10fc9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c4c8de3bf48d3756ab0f910fe5cc4937d70efdcd"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-90269 (GCVE-0-2026-90269)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:08 – Updated: 2026-09-17 16:08

Title

bpf: Reject load-acquire from pointers requiring fault protection

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject load-acquire from pointers requiring fault protection A BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier, unlike a regular BPF_LDX, so the JIT emits a plain load with no exception table entry and a fault panics the kernel instead of being handled. Reject the source pointer types that a BPF_LDX would have had that fault protection applied to, i.e. the ones bpf_convert_ctx_accesses() turns into BPF_PROBE_MEM: a bare PTR_TO_BTF_ID, PTR_TO_BTF_ID | PTR_UNTRUSTED, PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED and PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED. This is reachable e.g. by loading ->mm out of a trusted task_struct yields an untrusted pointer to mm_struct, and it is NULL for a kernel thread: [...] SEC("tp_btf/sched_switch") int BPF_PROG(demo, bool preempt, struct task_struct *prev, struct task_struct *next) { struct mm_struct *mm = next->mm; /* untrusted */ out_ldx = (__u64)mm->pgd; /* BPF_LDX */ out_acq = load_acquire(&mm->pgd); /* BPF_LOAD_ACQ */ return 0; } [...] Both dereference the same pointer, but only the BPF_LDX is protected (x86-64 JIT, jump targets shown prog-relative): [...] ; out_ldx = (__u64)mm->pgd; 17: movq $-10485760, %r10 1e: movq %rsi, %r11 21: addq $184, %r11 28: subq %r10, %r11 2b: movabsq $140737498841088, %r10 35: cmpq %r10, %r11 38: ja 0x3e <-- kernel addr? 3a: xorl %edi, %edi <-- no: dst = 0, skip the load 3c: jmp 0x45 3e: movq 184(%rsi), %rdi <-- yes: load + extable entry [...] ; load_acquire(&mm->pgd) 53: movq %rsi, %rdi 56: movq 184(%rdi), %rax <-- no check, no extable entry [...] Note that BPF_PROBE_MEM is not visible in a bpftool xlated dump, as bpf_insn_prepare_dump() rewrites it back to BPF_MEM. A PTR_TRUSTED pointer is deliberately not on the list. Such a load is not converted either, but it does not need to be, since the pointer is guaranteed live, so load-acquire from it stays allowed. The check is gated on BPF_LOAD_ACQ so that atomic RMW and store-release error messages are unchanged; writes (RMW / store-release) to such pointers are already rejected elsewhere, so only load-acquire needs this.

Severity

No CVSS data available.

Assigner

Linux mitre root Scorecard

References

3 references

URL	Tags
https://git.kernel.org/stable/c/c4c8de3bf48d3756a…
https://git.kernel.org/stable/c/5f8ade6e9b7931fc9…
https://git.kernel.org/stable/c/7db0a00445f1a40ba…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 880442305a3908589bf4d6fc1d79edb577ee497c , < c4c8de3bf48d3756ab0f910fe5cc4937d70efdcd (git) Affected: 880442305a3908589bf4d6fc1d79edb577ee497c , < 5f8ade6e9b7931fc9697394f1b2c4ae833f5ac18 (git) Affected: 880442305a3908589bf4d6fc1d79edb577ee497c , < 7db0a00445f1a40bacfe9b747405c11cb5f10fc9 (git)
Linux	Linux	Affected: 6.15 Unaffected: 0 , < 6.15 (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": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c4c8de3bf48d3756ab0f910fe5cc4937d70efdcd",
              "status": "affected",
              "version": "880442305a3908589bf4d6fc1d79edb577ee497c",
              "versionType": "git"
            },
            {
              "lessThan": "5f8ade6e9b7931fc9697394f1b2c4ae833f5ac18",
              "status": "affected",
              "version": "880442305a3908589bf4d6fc1d79edb577ee497c",
              "versionType": "git"
            },
            {
              "lessThan": "7db0a00445f1a40bacfe9b747405c11cb5f10fc9",
              "status": "affected",
              "version": "880442305a3908589bf4d6fc1d79edb577ee497c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject load-acquire from pointers requiring fault protection\n\nA BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier,\nunlike a regular BPF_LDX, so the JIT emits a plain load with no exception\ntable entry and a fault panics the kernel instead of being handled.\n\nReject the source pointer types that a BPF_LDX would have had that fault\nprotection applied to, i.e. the ones bpf_convert_ctx_accesses() turns\ninto BPF_PROBE_MEM: a bare PTR_TO_BTF_ID, PTR_TO_BTF_ID | PTR_UNTRUSTED,\nPTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED and PTR_TO_MEM | MEM_RDONLY |\nPTR_UNTRUSTED.\n\nThis is reachable e.g. by loading -\u003emm out of a trusted task_struct\nyields an untrusted pointer to mm_struct, and it is NULL for a kernel\nthread:\n\n  [...]\n  SEC(\"tp_btf/sched_switch\")\n  int BPF_PROG(demo, bool preempt, struct task_struct *prev,\n               struct task_struct *next)\n  {\n      struct mm_struct *mm = next-\u003emm;  /* untrusted */\n\n      out_ldx = (__u64)mm-\u003epgd;         /* BPF_LDX      */\n      out_acq = load_acquire(\u0026mm-\u003epgd); /* BPF_LOAD_ACQ */\n      return 0;\n  }\n  [...]\n\nBoth dereference the same pointer, but only the BPF_LDX is protected\n(x86-64 JIT, jump targets shown prog-relative):\n\n  [...]\n  ; out_ldx = (__u64)mm-\u003epgd;\n  17:   movq    $-10485760, %r10\n  1e:   movq    %rsi, %r11\n  21:   addq    $184, %r11\n  28:   subq    %r10, %r11\n  2b:   movabsq $140737498841088, %r10\n  35:   cmpq    %r10, %r11\n  38:   ja      0x3e                 \u003c-- kernel addr?\n  3a:   xorl    %edi, %edi           \u003c-- no: dst = 0, skip the load\n  3c:   jmp     0x45\n  3e:   movq    184(%rsi), %rdi      \u003c-- yes: load + extable entry\n  [...]\n  ; load_acquire(\u0026mm-\u003epgd)\n  53:\tmovq    %rsi, %rdi\n  56:\tmovq    184(%rdi), %rax       \u003c-- no check, no extable entry\n  [...]\n\nNote that BPF_PROBE_MEM is not visible in a bpftool xlated dump, as\nbpf_insn_prepare_dump() rewrites it back to BPF_MEM.\n\nA PTR_TRUSTED pointer is deliberately not on the list. Such a load is\nnot converted either, but it does not need to be, since the pointer is\nguaranteed live, so load-acquire from it stays allowed.\n\nThe check is gated on BPF_LOAD_ACQ so that atomic RMW and store-release\nerror messages are unchanged; writes (RMW / store-release) to such\npointers are already rejected elsewhere, so only load-acquire needs this."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T16:08:03.996Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/c4c8de3bf48d3756ab0f910fe5cc4937d70efdcd"
        },
        {
          "url": "https://git.kernel.org/stable/c/5f8ade6e9b7931fc9697394f1b2c4ae833f5ac18"
        },
        {
          "url": "https://git.kernel.org/stable/c/7db0a00445f1a40bacfe9b747405c11cb5f10fc9"
        }
      ],
      "title": "bpf: Reject load-acquire from pointers requiring fault protection",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90269",
    "datePublished": "2026-09-17T16:08:03.996Z",
    "dateReserved": "2026-09-11T19:38:34.796Z",
    "dateUpdated": "2026-09-17T16:08:03.996Z",
    "state": "PUBLISHED"
  },
  "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.
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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-2XHX-G2J2-V5CP

CVE-2026-90269 (GCVE-0-2026-90269)

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