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VulnerabilityPublished Updated

CVE-2026-23383: Linux kernel · bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d, ef06fd16d48704eac868441d98d4ef083d8f3d07, 66959ed481a474eaae278c7f6860a2a9b188a4d6 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ b2ad54e1533e91449cb2a371e034942bd7882b58, < f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d
Fixed in
  • f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d
LinuxLinuxAffected
  • ≥ b2ad54e1533e91449cb2a371e034942bd7882b58, < ef06fd16d48704eac868441d98d4ef083d8f3d07
Fixed in
  • ef06fd16d48704eac868441d98d4ef083d8f3d07
LinuxLinuxAffected
  • ≥ b2ad54e1533e91449cb2a371e034942bd7882b58, < 66959ed481a474eaae278c7f6860a2a9b188a4d6
Fixed in
  • 66959ed481a474eaae278c7f6860a2a9b188a4d6
LinuxLinuxAffected
  • ≥ b2ad54e1533e91449cb2a371e034942bd7882b58, < 519b1ad91de5bf7a496f2b858e9212db6328e1de
Fixed in
  • 519b1ad91de5bf7a496f2b858e9212db6328e1de
LinuxLinuxAffected
  • ≥ b2ad54e1533e91449cb2a371e034942bd7882b58, < 80ad264da02cc4aee718e799c2b79f0f834673dc
Fixed in
  • 80ad264da02cc4aee718e799c2b79f0f834673dc
LinuxLinuxAffected
  • =6.0
Fixed in–

Description

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

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