CVE-2025-27512: Zincati allows unprivileged access to rpm-ostree D-Bus `Deploy()` and `FinalizeDeployment()` methods

2.1 CVSS

Description

Zincati is an auto-update agent for Fedora CoreOS hosts. Zincati ships a polkit rule which allows the `zincati` system user to use the actions `org.projectatomic.rpmostree1.deploy` to deploy updates to the system and `org.projectatomic.rpmostree1.finalize-deployment` to reboot the system into the deployed update. Since Zincati v0.0.24, this polkit rule contains a logic error which broadens access of those polkit actions to any unprivileged user rather than just the `zincati` system user. In practice, this means that any unprivileged user with access to the system D-Bus socket is able to deploy older Fedora CoreOS versions (which may have other known vulnerabilities). Note that rpm-ostree enforces that the selected version must be from the same branch the system is currently on so this cannot directly be used to deploy an attacker-controlled update payload. This primarily impacts users running untrusted workloads with access to the system D-Bus socket. Note that in general, untrusted workloads should not be given this access, whether containerized or not. By default, containers do not have access to the system D-Bus socket. The logic error is fixed in Zincati v0.0.30. A workaround is to manually add a following polkit rule, instructions for which are available in the GitHub Security Advisory.

Classification

CVE ID: CVE-2025-27512

CVSS Base Severity: LOW

CVSS Base Score: 2.1

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U

Problem Types

CWE-783: Operator Precedence Logic Error CWE-863: Incorrect Authorization

Affected Products

Vendor: coreos

Product: zincati

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 3.66% (scored less or equal to compared to others)

EPSS Date: 2025-04-15 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-27512
https://github.com/coreos/zincati/security/advisories/GHSA-w6fv-6gcc-x825
https://github.com/coreos/zincati/commit/01d8e89f799e6ba21bdf7dc668abce23bd0d8f78
https://github.com/coreos/zincati/commit/28a43aa2c1edda091ba659677d73c13e6e3ea99d
https://github.com/coreos/zincati/releases/tag/v0.0.24
https://github.com/coreos/zincati/releases/tag/v0.0.30

Timeline