UBUNTU-CVE-2026-99245: Medium severity ubuntu/linux vulnerability
In the Linux kernel, the following vulnerability has been resolved: KEYS: Fix keyrejectandlink() race with keyring restriction The restrictlink check in keyrejectandlink() is done before taking the keyring semaphore, racing with a concurrent keyringrestrict() that installs the restriction while holding the semaphore in write mode. Move the check to after keylinklock(), so it is done under the semaphore, matching the pattern used in keycreateorupdate().
Affected Software
Event History
Frequently Asked Questions
Which Ubuntu kernel packages are identified as affected?
The listed packages are ubuntu/linux, ubuntu/linux-fips, ubuntu/linux-aws, ubuntu/linux-azure, ubuntu/linux-gcp, ubuntu/linux-oracle, ubuntu/linux-aws-fips, and ubuntu/linux-azure-fips.
What concurrent activity is required for the race to occur?
The race requires key_reject_and_link() to perform its restriction check concurrently with keyring_restrict() installing a keyring restriction. The restriction installation occurs while the keyring semaphore is held in write mode.
What is the remediation described by the fix?
The fix moves the restrict_link check until after __key_link_lock() has been acquired. This performs the check under the keyring semaphore and prevents it from racing with restriction installation.