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CVE-2026-23417 (GCVE-0-2026-23417)

Vulnerability from cvelistv5 – Published: 2026-04-02 11:40 – Updated: 2026-05-11 22:06
VLAI
Title
bpf: Fix constant blinding for PROBE_MEM32 stores
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix constant blinding for PROBE_MEM32 stores BPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by bpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to survive unblinded into JIT-compiled native code when bpf_jit_harden >= 1. The root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM to BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification, before bpf_jit_blind_constants() runs during JIT compilation. The blinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not BPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through unblinded. Add BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the existing BPF_ST|BPF_MEM cases. The blinding transformation is identical: load the blinded immediate into BPF_REG_AX via mov+xor, then convert the immediate store to a register store (BPF_STX). The rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so the architecture JIT emits the correct arena addressing (R12-based on x86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes BPF_MEM mode; construct the instruction directly instead.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < 56af722756ed82fee2ae5d5b4d04743407506195 (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < ccbf29b28b5554f9d65b2fb53b994673ad58b3bf (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < de641ea08f8fff6906e169d2576c2ac54e562fbb (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < 2321a9596d2260310267622e0ad8fbfa6f95378f (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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      "title": "kernel: bpf: Fix constant blinding for PROBE_MEM32 stores",
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      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-23417.json",
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}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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