Vulnerability-Lookup

FKIE_CVE-2026-23383

Vulnerability from fkie_nvd - Published: 2026-03-25 11:16 - Updated: 2026-04-24 18:42

Severity ?

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/519b1ad91de5bf7a496f2b858e9212db6328e1de	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/66959ed481a474eaae278c7f6860a2a9b188a4d6	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/80ad264da02cc4aee718e799c2b79f0f834673dc	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ef06fd16d48704eac868441d98d4ef083d8f3d07	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	6.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0

JSON

To clipboard

{
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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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nbpf, arm64: Forzar alineaci\u00f3n de 8 bytes para el b\u00fafer JIT para prevenir el desgarro at\u00f3mico\n\nstruct bpf_plt contiene un campo objetivo u64. Actualmente, el asignador JIT de BPF solicita una alineaci\u00f3n de 4 bytes (sizeof(u32)) para el b\u00fafer JIT.\n\nDebido a que la direcci\u00f3n base del b\u00fafer JIT puede estar alineada a 4 bytes (p. ej., terminando en 0x4 o 0xc), la l\u00f3gica de relleno relativo en build_plt() no logra asegurar que target caiga en un l\u00edmite de 8 bytes.\n\nEsto lleva a dos problemas:\n1. UBSAN informa advertencias de acceso desalineado al desreferenciar la estructura.\n2. M\u00e1s cr\u00edticamente, target se actualiza concurrentemente a trav\u00e9s de WRITE_ONCE() en bpf_arch_text_poke() mientras el c\u00f3digo JIT\u0027d ejecuta ldr. En arm64, las cargas/almacenamientos de 64 bits solo se garantiza que sean at\u00f3micos de copia \u00fanica si est\u00e1n alineados a 64 bits. Un target desalineado arriesga una lectura desgarrada, haciendo que el JIT salte a una direcci\u00f3n corrupta.\n\nSolucione esto aumentando el requisito de alineaci\u00f3n de asignaci\u00f3n a 8 bytes (sizeof(u64)) en bpf_jit_binary_pack_alloc(). Esto ancla la base del b\u00fafer JIT a un l\u00edmite de 8 bytes, permitiendo que las matem\u00e1ticas de relleno relativo en build_plt() alineen correctamente el campo target."
    }
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  "id": "CVE-2026-23383",
  "lastModified": "2026-04-24T18:42:21.773",
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          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
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          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
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}

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

Vulnerability from cvelistv5 – Published: 2026-03-25 10:28 – Updated: 2026-05-11 22:05

Title

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

Summary

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

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)

Show details on NVD website

JSON

To clipboard

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          "programFiles": [
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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.

Action not permitted

FKIE_CVE-2026-23383

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

Tags

Sightings

Nomenclature