Executive brief
PackageKit is a system service used across many Linux distributions to manage software installations and updates. A security flaw allows a standard user to bypass normal security checks and install malicious software with full administrative (root) privileges. This could allow an attacker to take complete control of the computer, access any data, or disrupt operations.
Technical details
PackageKit contains a TOCTOU race condition in 'src/pk-transaction.c' related to how transaction flags are handled. The vulnerability stems from three primary issues: 'InstallFiles()' allows unconditional overwriting of 'cached_transaction_flags' even while a transaction is running; the state machine silently rejects backward state transitions without reverting flag changes; and the scheduler reads these flags at execution time rather than authorization time. A local unprivileged attacker can exploit this race to overwrite flags between the authorization and execution phases, allowing the installation of arbitrary RPM packages (including those with malicious scriptlets) without proper authentication. This issue is resolved in version 1.3.5.
Affected products
- PackageKit PackageKit 1.0.2 - 1.3.4
Timeline
- 2026-04-22: disclosed
- 2026-04-22: advisory
- 2026-04-22: patched: Fixed in version 1.3.5
References
- https://github.com/PackageKit/PackageKit/blob/04057883189efa225a7c785591aa87cb299782f8/src/pk-transaction.c
- https://github.com/PackageKit/PackageKit/blob/04057883189efa225a7c785591aa87cb299782f8/src/pk-transaction.c
- https://github.com/PackageKit/PackageKit/blob/04057883189efa225a7c785591aa87cb299782f8/src/pk-transaction.c
- https://github.com/PackageKit/PackageKit/security/advisories/GHSA-f55j-vvr9-69xv
- https://github.security.telekom.com/2026/04/pack2theroot-linux-local-privilege-escalation.html
- http://www.openwall.com/lists/oss-security/2026/04/22/6
- https://access.redhat.com/errata/RHSA-2026:11504