{"apiVersion":"1.0","identifier":"CVE-2026-99040","description":"In the Linux kernel, the following vulnerability has been resolved: KEYS: Fix add_key() race with keyring restriction __key_create_or_update() snapshots keyring->restrict_link before taking the destination keyring-s semaphore. keyring_restrict() installs a restriction while holding that semaphore. This allows a writer to observe no restriction, wait for the keyring owner to install a reject-all restriction and return successfully, and then link a key using the stale NULL snapshot. The writer only needs write permission on the destination keyring. Move the restrict_link read after __key_link_lock() and __key_link_begin(). The read and the subsequent restriction check are then serialized with restriction installation by keyring->sem. The race was reproduced on v7.2.8 in 19 executions where restriction installation returned before the link completed. All 19 linked the key despite the reject-all restriction. With this change, 312 executions reached the same ordering and every add_key() call failed with -EPERM. The issue was found by manual concurrency analysis assisted by AI-based analysis and independently verified with a QEMU reproducer and kernel instrumentation.","publishedAt":"2026-10-23T13:17:27","lastModifiedAt":"2026-10-30T13:21:41","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-99040","cvssScore":null,"cvssVector":null,"epssProbability":0.00191,"riskScore":null,"affectedProduct":"Linux kernel","affectedVersions":"unknown","vulnerabilityType":"Kernel","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-99040","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-99040","en":"https://www.redsauce.net/en/cves/CVE-2026-99040","fr":"https://www.redsauce.net/fr/cves/CVE-2026-99040","pt":"https://www.redsauce.net/pt/cves/CVE-2026-99040","de":"https://www.redsauce.net/de/cves/CVE-2026-99040","sk":"https://www.redsauce.net/sk/cves/CVE-2026-99040","el":"https://www.redsauce.net/el/cves/CVE-2026-99040"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-99040"}}