If a malicious SDK container declares an extension point with a crafted directory path and a developer runs flatpak build-init with the --writable-sdk and --sdk-extension options, the path‑resolution logic fails to sanitize the input. This flaw allows the attacker to write files to locations outside the working directory, effectively granting arbitrary file write privileges in the host context.

Red Hat Enterprise Linux 9, 8, 7, 10 systems that use Flatpak are vulnerable when the SDK container includes a crafted extension point. The vulnerability is present regardless of the operating system version but requires execution of flatpak build‑init with the vulnerable options.

The flaw is a path‑traversal weakness (CWE‑22). A CVSS score of 6.5 indicates moderate severity. The EPSS score is listed as < 1 %, showing a very low but non‑zero probability of exploitation, and the vulnerability is not listed in CISA KEV. Exploitation requires that an attacker can run flatpak build‑init with a malicious SDK; this is typically limited to developers or trusted build personnel who have permission to use the build‑init tool. Once exploited, the attacker can create or overwrite arbitrary files in the host filesystem, potentially compromising system integrity or facilitating further attacks.