CVE-2026-85731 PUBLISHED

oras-go: Arbitrary file write outside file.Store root via symlink-chain bypass in tar extraction (pushDir)

Assigner: GitHub_M
Reserved: 04.09.2026 Published: 16.09.2026 Updated: 16.09.2026

oras-go is a Go library for managing OCI artifacts. Prior to 2.6.2, content/file.Store extraction of OCI layers marked with io.deis.oras.content.unpack=true can write outside the store working directory. The pushDir path through extractTarDirectory and ensureLinkPath validates symlink targets lexically, resolveRelToBase skips its parent-symlink walk for root-level entries, and writeFile follows a terminal symlink when opening a regular file. A malicious archive can therefore create a symlink chain whose lexical target remains inside the extraction root but whose resolved target is an attacker-selected absolute path, then overwrite that target with a same-named regular-file entry even when AllowPathTraversalOnWrite is false. Pulling an attacker-controlled artifact can create or overwrite any file writable by the process and may lead to code execution. This issue is fixed in version 2.6.2.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS Score: 8.8

Product Status

Vendor oras-project
Product oras-go
Versions
  • Version < 2.6.2 is affected

References

Problem Types

  • CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') CWE
  • CWE-59: Improper Link Resolution Before File Access ('Link Following') CWE