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

Vulnerability from cvelistv5 – Published: 2026-03-25 10:28 – Updated: 2026-03-25 10:28
VLAI?
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
References
Impacted products
Vendor Product Version
Linux Linux Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 80ad264da02cc4aee718e799c2b79f0f834673dc (git)
Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 519b1ad91de5bf7a496f2b858e9212db6328e1de (git)
Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < 66959ed481a474eaae278c7f6860a2a9b188a4d6 (git)
Affected: b2ad54e1533e91449cb2a371e034942bd7882b58 , < ef06fd16d48704eac868441d98d4ef083d8f3d07 (git)
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    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-rc2 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "arch/arm64/net/bpf_jit_comp.c"
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          "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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        "dateUpdated": "2026-03-25T10:28:02.126Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/80ad264da02cc4aee718e799c2b79f0f834673dc"
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        },
        {
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    "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"
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  }
}


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