Flatpak vulnerable to path traversal via unvalidated "arch" parameter in DeployAppstream

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. Prior to version 1.18.1, on systems where at least one OCI remote is configured (most common on Fedora systems), a malicious local user in an active local session could use a crafted architecture name to trick the `flatpak-system-helper` process into creating a root-owned directory tree with contents determined by the OCI remote, plus a root-owned `lock` file and `icons` directory, outside the intended root directory. If this vulnerability is combined with other vulnerabilities also fixed in 1.18.1, the combination can lead to local root privilege escalation. This particular vulnerability is not believed to be exploitable if there are no OCI remotes configured (common on non-Fedora systems). Version 1.18.1 patches the issue.

Source published

20 Oct 2026 14:39:50 UTC

Source modified

20 Oct 2026 15:32:18 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 4.0 · 7.2 CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N