CVE-2026-63805
Received Received - Intake

Memory Corruption in Linux Kernel Crypto Subsystem

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: crypto: nx - fix nx_crypto_ctx_exit argument nx_crypto_ctx_shash_exit calls nx_crypto_ctx_exit with crypto_shash_ctx(...) but crypto_shash_ctx gives a nx_crypto_ctx *, not a crypto_tfm *. Fix the type in nx_crypto_ctx_exit and drop the bogus crypto_tfm_ctx call. This fixes the following oops: BUG: Unable to handle kernel data access at 0xc0403effffffffc8 Faulting instruction address: 0xc000000000396cb4 Oops: Kernel access of bad area, sig: 11 [#15] Call Trace: nx_crypto_ctx_shash_exit+0x24/0x60 crypto_shash_exit_tfm+0x28/0x40 crypto_destroy_tfm+0x98/0x140 crypto_exit_ahash_using_shash+0x20/0x40 crypto_destroy_tfm+0x98/0x140 hash_release+0x1c/0x30 alg_sock_destruct+0x38/0x60 __sk_destruct+0x48/0x2b0 af_alg_release+0x58/0xb0 __sock_release+0x68/0x150 sock_close+0x20/0x40 __fput+0x110/0x3a0 sys_close+0x48/0xa0 system_call_exception+0x140/0x2d0 system_call_common+0xf4/0x258 .. which came from hardlink(1) opportunistically using AF_ALG. The same problem exists with nx_crypto_ctx_skcipher_exit getting a context it wasn't expecting, but apparently nobody hit that for years.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-63805
EUVD
EUVD-2026-45471

Affected Vendors & Products

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

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a type mismatch in the nx_crypto_ctx_exit function. The function was incorrectly called with a crypto_shash_ctx pointer instead of the expected crypto_tfm pointer, leading to a kernel oops when accessing invalid memory. The issue was triggered by hardlink(1) using AF_ALG, causing a system crash with a kernel data access error.

Detection Guidance

This vulnerability is specific to the Linux kernel's crypto subsystem and manifests as a kernel oops. Detection requires checking kernel logs for oops messages or crashes related to crypto operations. Monitor system logs with commands like dmesg or journalctl for kernel errors.

Impact Analysis

This vulnerability can cause system crashes (kernel oops) when certain operations like hardlinking trigger the affected code path. It may lead to denial of service conditions where the system becomes unresponsive or requires a reboot.

Compliance Impact

This vulnerability is a Linux kernel issue causing a kernel oops due to incorrect context handling in crypto operations. It does not directly affect compliance with GDPR, HIPAA, or similar standards as it is a low-level system crash rather than a data exposure or privacy violation.

Mitigation Strategies

Apply the kernel patch that fixes the nx_crypto_ctx_exit type issue. Update to a patched Linux kernel version. If immediate patching is not possible, avoid using AF_ALG interfaces until the fix is applied to prevent potential kernel crashes.

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