Vulnerability-Lookup

GHSA-887M-4QRH-HJQ5

Vulnerability from github – Published: 2026-03-25 12:30 – Updated: 2026-04-02 15:31

Details

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

bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing

struct bpf_plt contains a u64 target field. Currently, the BPF JIT allocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT buffer.

Because the base address of the JIT buffer can be 4-byte aligned (e.g., ending in 0x4 or 0xc), the relative padding logic in build_plt() fails to ensure that target lands on an 8-byte boundary.

This leads to two issues: 1. UBSAN reports misaligned-access warnings when dereferencing the structure. 2. More critically, target is updated concurrently via WRITE_ONCE() in bpf_arch_text_poke() while the JIT'd code executes ldr. On arm64, 64-bit loads/stores are only guaranteed to be single-copy atomic if they are 64-bit aligned. A misaligned target risks a torn read, causing the JIT to jump to a corrupted address.

Fix this by increasing the allocation alignment requirement to 8 bytes (sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of the JIT buffer to an 8-byte boundary, allowing the relative padding math in build_plt() to correctly align the target field.

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-2026-23383"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-25T11:16:38Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing\n\nstruct bpf_plt contains a u64 target field. Currently, the BPF JIT\nallocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT\nbuffer.\n\nBecause the base address of the JIT buffer can be 4-byte aligned (e.g.,\nending in 0x4 or 0xc), the relative padding logic in build_plt() fails\nto ensure that target lands on an 8-byte boundary.\n\nThis leads to two issues:\n1. UBSAN reports misaligned-access warnings when dereferencing the\n   structure.\n2. More critically, target is updated concurrently via WRITE_ONCE() in\n   bpf_arch_text_poke() while the JIT\u0027d code executes ldr. On arm64,\n   64-bit loads/stores are only guaranteed to be single-copy atomic if\n   they are 64-bit aligned. A misaligned target risks a torn read,\n   causing the JIT to jump to a corrupted address.\n\nFix this by increasing the allocation alignment requirement to 8 bytes\n(sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of\nthe JIT buffer to an 8-byte boundary, allowing the relative padding math\nin build_plt() to correctly align the target field.",
  "id": "GHSA-887m-4qrh-hjq5",
  "modified": "2026-04-02T15:31:36Z",
  "published": "2026-03-25T12:30:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23383"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/519b1ad91de5bf7a496f2b858e9212db6328e1de"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/66959ed481a474eaae278c7f6860a2a9b188a4d6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/80ad264da02cc4aee718e799c2b79f0f834673dc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ef06fd16d48704eac868441d98d4ef083d8f3d07"
    }
  ],
  "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-2026-23383 (GCVE-0-2026-23383)

Vulnerability from cvelistv5 – Published: 2026-03-25 10:28 – Updated: 2026-08-05 12:21

Title

bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing struct bpf_plt contains a u64 target field. Currently, the BPF JIT allocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT buffer. Because the base address of the JIT buffer can be 4-byte aligned (e.g., ending in 0x4 or 0xc), the relative padding logic in build_plt() fails to ensure that target lands on an 8-byte boundary. This leads to two issues: 1. UBSAN reports misaligned-access warnings when dereferencing the structure. 2. More critically, target is updated concurrently via WRITE_ONCE() in bpf_arch_text_poke() while the JIT'd code executes ldr. On arm64, 64-bit loads/stores are only guaranteed to be single-copy atomic if they are 64-bit aligned. A misaligned target risks a torn read, causing the JIT to jump to a corrupted address. Fix this by increasing the allocation alignment requirement to 8 bytes (sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of the JIT buffer to an 8-byte boundary, allowing the relative padding math in build_plt() to correctly align the target field.

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

4 references

URL	Tags
https://git.kernel.org/stable/c/80ad264da02cc4aee…
https://git.kernel.org/stable/c/519b1ad91de5bf7a4…
https://git.kernel.org/stable/c/66959ed481a474eaa…
https://git.kernel.org/stable/c/ef06fd16d48704eac…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 80ad264da02cc4aee718e799c2b79f0f834673dc (git) Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 519b1ad91de5bf7a496f2b858e9212db6328e1de (git) Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 66959ed481a474eaae278c7f6860a2a9b188a4d6 (git) Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < ef06fd16d48704eac868441d98d4ef083d8f3d07 (git)
Linux	Linux	Affected: 6.0 Unaffected: 0 , < 6.0 (semver) Unaffected: 6.12.77 , ≤ 6.12.* (semver) Unaffected: 6.18.17 , ≤ 6.18.* (semver) Unaffected: 6.19.7 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

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    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/net/bpf_jit_comp.c"
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          "versions": [
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            {
              "lessThan": "519b1ad91de5bf7a496f2b858e9212db6328e1de",
              "status": "affected",
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              "versionType": "git"
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          ],
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
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              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
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            {
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              "version": "6.19.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.77",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.0",
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                },
                {
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                }
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              "negate": false,
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing\n\nstruct bpf_plt contains a u64 target field. Currently, the BPF JIT\nallocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT\nbuffer.\n\nBecause the base address of the JIT buffer can be 4-byte aligned (e.g.,\nending in 0x4 or 0xc), the relative padding logic in build_plt() fails\nto ensure that target lands on an 8-byte boundary.\n\nThis leads to two issues:\n1. UBSAN reports misaligned-access warnings when dereferencing the\n   structure.\n2. More critically, target is updated concurrently via WRITE_ONCE() in\n   bpf_arch_text_poke() while the JIT\u0027d code executes ldr. On arm64,\n   64-bit loads/stores are only guaranteed to be single-copy atomic if\n   they are 64-bit aligned. A misaligned target risks a torn read,\n   causing the JIT to jump to a corrupted address.\n\nFix this by increasing the allocation alignment requirement to 8 bytes\n(sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of\nthe JIT buffer to an 8-byte boundary, allowing the relative padding math\nin build_plt() to correctly align the target field."
        }
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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"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - BPF is accessed via the bpf() syscall, requiring local system access. There is no remote or adjacent network path to trigger BPF program loading or trampoline attachment.\nAC:L - The attacker controls both sides of the race \u2014 they load the BPF program (creating the misaligned PLT) and trigger the text_poke (by attaching a trampoline). The ~50% misalignment chance is overcome by loading multiple programs. No conditions beyond attacker control are needed.\nPR:L - While CAP_BPF and CAP_PERFMON are required, the BPF token delegation mechanism allows these capabilities to be granted to users in user namespaces. This is a supported, reasonable deployment scenario for containerized BPF workloads.\nUI:N - No user interaction is required. The attacker independently loads BPF programs and attaches trampolines.\nS:U - The vulnerability results in kernel-level control flow corruption within the same security authority. No VM escape, IOMMU bypass, or sandbox boundary crossing occurs.\nC:H - The torn PLT target causes a kernel-mode jump to a corrupted address, which is a control-flow hijack in kernel context. This could be leveraged to read arbitrary kernel memory through code execution.\nI:H - A kernel-mode jump to a corrupted address constitutes control-flow hijacking that could be leveraged for arbitrary code execution in kernel context, enabling arbitrary memory writes.\nA:H - Jumping to a corrupted address in kernel mode will almost certainly cause a kernel panic/oops, resulting in complete denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:21:21.051Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/66959ed481a474eaae278c7f6860a2a9b188a4d6"
        },
        {
          "url": "https://git.kernel.org/stable/c/ef06fd16d48704eac868441d98d4ef083d8f3d07"
        }
      ],
      "title": "bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing",
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23383",
    "datePublished": "2026-03-25T10:28:02.126Z",
    "dateReserved": "2026-01-13T15:37:46.007Z",
    "dateUpdated": "2026-08-05T12:21:21.051Z",
    "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.
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.

Detection rules are retrieved from Rulezet.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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