Vulnerability-Lookup

GHSA-887M-4QRH-HJQ5

Vulnerability from github – Published: 2026-03-25 12:30 – Updated: 2026-03-25 12:30

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.

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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": null
  },
  "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": "2026-03-25T12:30:24Z",
  "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": []
}

CVE-2026-23383 (GCVE-0-2026-23383)

Vulnerability from cvelistv5 – Published: 2026-03-25 10:28 – Updated: 2026-03-25 10:28

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 ?

No CVSS data available.

Assigner

Linux

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

Vendor

Product

Version

Linux

Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 80ad264da02cc4aee718e799c2b79f0f834673dc (git)
Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 519b1ad91de5bf7a496f2b858e9212db6328e1de (git)
Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 66959ed481a474eaae278c7f6860a2a9b188a4d6 (git)
Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < ef06fd16d48704eac868441d98d4ef083d8f3d07 (git)

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-rc2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/net/bpf_jit_comp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "80ad264da02cc4aee718e799c2b79f0f834673dc",
              "status": "affected",
              "version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
              "versionType": "git"
            },
            {
              "lessThan": "519b1ad91de5bf7a496f2b858e9212db6328e1de",
              "status": "affected",
              "version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
              "versionType": "git"
            },
            {
              "lessThan": "66959ed481a474eaae278c7f6860a2a9b188a4d6",
              "status": "affected",
              "version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
              "versionType": "git"
            },
            {
              "lessThan": "ef06fd16d48704eac868441d98d4ef083d8f3d07",
              "status": "affected",
              "version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/net/bpf_jit_comp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.77",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.17",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "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:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.17",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.7",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
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        {
          "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-25T10:28:02.126Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/80ad264da02cc4aee718e799c2b79f0f834673dc"
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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",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "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": "2026-03-25T10:28:02.126Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-887M-4QRH-HJQ5

CVE-2026-23383 (GCVE-0-2026-23383)

Tags

Sightings

Nomenclature