OCI layer symlink escape → arbitrary host write

Affected versions of `boxlite` extract OCI image layer tarballs without fully containing path resolution to the extraction root. A crafted layer containing a symlink whose target is an absolute on-host path (e.g. `escape -> /tmp`) followed by a file entry that resolves through that symlink (e.g. `escape/<path>/pwned.txt`) caused the extractor to write the payload to the host filesystem outside the intended rootfs directory. The fix in v0.9.0 routes every destructive filesystem operation through a `SafeRoot` handle (`openat2(RESOLVE_IN_ROOT)` on Linux, lexical fallback elsewhere) so that no tar entry can resolve outside the extraction root, even with adversarial symlinks placed by earlier entries in the same layer. This is a container-escape during image extraction, exploitable by any user who pulls or loads a malicious OCI image — including via `SimpleBox(rootfs_path=...)` from an untrusted local layout.

Source published

16 May 2026 12:00:00 UTC

Source modified

12 Oct 2026 18:00:13 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

OSV · upstream source license applies

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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H