CVE-2026-43306
Received Received - Intake

BPF Crypto Context Release Type Mismatch in Linux Kernel

Publication date: 2026-05-08

Last updated on: 2026-05-08

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: bpf: crypto: Use the correct destructor kfunc type With CONFIG_CFI enabled, the kernel strictly enforces that indirect function calls use a function pointer type that matches the target function. I ran into the following type mismatch when running BPF self-tests: CFI failure at bpf_obj_free_fields+0x190/0x238 (target: bpf_crypto_ctx_release+0x0/0x94; expected type: 0xa488ebfc) Internal error: Oops - CFI: 00000000f2008228 [#1] SMP ... As bpf_crypto_ctx_release() is also used in BPF programs and using a void pointer as the argument would make the verifier unhappy, add a simple stub function with the correct type and register it as the destructor kfunc instead.

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Meta Information

Published
2026-05-08
Last Modified
2026-05-08
Generated
2026-07-09
AI Q&A
2026-05-08
EPSS Evaluated
2026-07-08
NVD
CVE-2026-43306
EUVD
EUVD-2026-28576

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is related to the Linux kernel's BPF (Berkeley Packet Filter) crypto subsystem. It involves the use of an incorrect destructor kernel function (kfunc) type when CONFIG_CFI (Control Flow Integrity) is enabled. The kernel enforces that indirect function calls must use a function pointer type matching the target function. A type mismatch was detected during BPF self-tests, causing a CFI failure and internal kernel error (Oops). The issue was that the function bpf_crypto_ctx_release was used with a void pointer argument, which the verifier did not accept. The fix involved adding a stub function with the correct type and registering it as the destructor kfunc.

Impact Analysis

This vulnerability can cause kernel crashes or internal errors due to type mismatches in function pointers when running BPF programs with CONFIG_CFI enabled. Such crashes can lead to system instability or denial of service conditions, impacting the reliability and availability of the affected Linux system.

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