CVE-2026-99220
Received Received - Intake

NULL Pointer Dereference in Linux Kernel PKCS#8 Parser

Publication date: 2026-11-02

Last updated on: 2026-11-02

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: asymmetric_keys: reject trust keys without IDs The PKCS#8 parser deliberately leaves the asym_key_ids payload slot empty. key_or_keyring_common() unconditionally dereferences that slot when a PKCS#8 key is supplied to a key_or_keyring restriction. Both the plain and :chain forms reach this branch, allowing an unprivileged caller to trigger a NULL pointer dereference through KEYCTL_RESTRICT_KEYRING followed by add_key(). Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000 KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:key_or_keyring_common (crypto/asymmetric_keys/restrict.c:205 crypto/asymmetric_keys/restrict.c:279) Call Trace: <TASK> __key_create_or_update (security/keys/key.c:884) key_create_or_update (security/keys/key.c:1021) __do_sys_add_key (security/keys/keyctl.c:134) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) </TASK> Kernel panic - not syncing: Fatal exception Reject an asymmetric restriction key without key IDs. A PKCS#8 private key cannot identify the signer of a candidate certificate and is not a valid trust anchor.

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Meta Information

Published
2026-11-02
Last Modified
2026-11-02
Generated
2026-11-02
AI Q&A
2026-11-02
EPSS Evaluated
N/A
NVD
CVE-2026-99220

Affected Vendors & Products

Showing 7 associated CPEs
Vendor Product Version / Range
Linux Linux 3c58b2362ba828ee2970c66c6a6fd7b04fde4413
Linux Linux 3c58b2362ba828ee2970c66c6a6fd7b04fde4413
Linux Linux 3c58b2362ba828ee2970c66c6a6fd7b04fde4413
Linux Linux 3c58b2362ba828ee2970c66c6a6fd7b04fde4413
Linux Linux 3c58b2362ba828ee2970c66c6a6fd7b04fde4413
Linux Linux 3c58b2362ba828ee2970c66c6a6fd7b04fde4413
Linux Linux 4.20

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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 NULL pointer dereference flaw in the PKCS#8 parser. When a PKCS#8 key is used with a key restriction, the system unconditionally tries to access an empty asym_key_ids slot, causing a kernel crash. This happens via KEYCTL_RESTRICT_KEYRING followed by add_key().

Detection Guidance

This vulnerability is specific to the Linux kernel and involves a NULL pointer dereference in the PKCS#8 parser. Detection requires checking kernel logs for general protection faults or kernel panics related to asymmetric key restrictions. Monitor logs for oops messages or KASAN reports indicating null-ptr-deref in restrict.c.

Impact Analysis

An unprivileged attacker could exploit this to crash the system, leading to a denial of service. The kernel panic halts the system, potentially causing data loss or service disruption if not mitigated.

Compliance Impact

This vulnerability causes a NULL pointer dereference in the Linux kernel's key management subsystem, leading to kernel panic and system crashes. It does not directly affect data privacy or security controls required by GDPR or HIPAA, as it is a denial-of-service issue rather than a data exposure or access control flaw.

Mitigation Strategies

Update your Linux kernel to the latest patched version to resolve this vulnerability. Monitor kernel logs for NULL pointer dereference errors related to key_or_keyring_common. Avoid using PKCS#8 private keys as trust anchors until patched.

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