CVE-2026-41651

NameCVE-2026-41651
DescriptionPackageKit is a a D-Bus abstraction layer that allows the user to manage packages in a secure way using a cross-distro, cross-architecture API. PackageKit between and including versions 1.0.2 and 1.3.4 is vulnerable to a time-of-check time-of-use (TOCTOU) race condition on transaction flags that allows unprivileged users to install packages as root and thus leads to a local privilege escalation. This is patched in version 1.3.5. A local unprivileged user can install arbitrary RPM packages as root, including executing RPM scriptlets, without authentication. The vulnerability is a TOCTOU race condition on `transaction->cached_transaction_flags` combined with a silent state-machine guard that discards illegal backward transitions while leaving corrupted flags in place. Three bugs exist in `src/pk-transaction.c`: 1. Unconditional flag overwrite (line 4036): `InstallFiles()` writes caller-supplied flags to `transaction->cached_transaction_flags` without checking whether the transaction has already been authorized/started. A second call blindly overwrites the flags even while the transaction is RUNNING. 2. Silent state-transition rejection (lines 873–882): `pk_transaction_set_state()` silently discards backward state transitions (e.g. `RUNNING` → `WAITING_FOR_AUTH`) but the flag overwrite at step 1 already happened. The transaction continues running with corrupted flags. 3. Late flag read at execution time (lines 2273–2277): The scheduler's idle callback reads cached_transaction_flags at dispatch time, not at authorization time. If flags were overwritten between authorization and execution, the backend sees the attacker's flags.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4545-1, DSA-6226-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
packagekit (PTS)bullseye1.2.2-2vulnerable
bullseye (security)1.2.2-2+deb11u1fixed
bookworm1.2.6-5vulnerable
bookworm (security)1.2.6-5+deb12u1fixed
trixie1.3.1-1vulnerable
trixie (security)1.3.1-1+deb13u1fixed
forky, sid1.3.5-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
packagekitsourcebullseye1.2.2-2+deb11u1DLA-4545-1
packagekitsourcebookworm1.2.6-5+deb12u1DSA-6226-1
packagekitsourcetrixie1.3.1-1+deb13u1DSA-6226-1
packagekitsource(unstable)1.3.5-1

Notes

https://lists.freedesktop.org/archives/packagekit/2026-April/026513.html
https://github.com/PackageKit/PackageKit/security/advisories/GHSA-f55j-vvr9-69xv
https://github.security.telekom.com/2026/04/pack2theroot-linux-local-privilege-escalation.html
Fixed by: https://github.com/PackageKit/PackageKit/commit/76cfb675fb31acc3ad5595d4380bfff56d2a8697 (v1.3.5)

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