Rclone EUVD-2026-44530

The rclone archive extract subcommand must be invoked by the victim against an attacker-controlled archive (UI:R); no other rclone operations are affected. The attacker must be able to deliver a crafted archive to a user who then voluntarily extracts it, making social engineering or supply-chain archive substitution the realistic delivery mechanism. No authentication to rclone is required (PR:N) and no special system configuration is needed. Exploitation is bounded to sibling paths within the same bucket or parent directory the user already has write access to - the attacker cannot escape the bucket itself or reach arbitrary filesystem locations outside the user's existing authorization scope. Exploitation is further limited to the archive extract feature introduced in recent Rclone versions; deployments that do not use rclone archive are not exposed.

The CVSS 3.1 vector AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:L captures the core constraints well: the attack is local in the sense that the victim must execute rclone archive extract against attacker-controlled content (UI:R), no elevated privileges are needed, and the scope change (S:C) reflects that extracted files can escape the destination prefix and land in sibling cloud-storage paths beyond the nominal vulnerable component. EPSS at 0.14% (4th percentile) is very low, consistent with the user-interaction prerequisite and the requirement to deliver a malicious archive to a specific user. The vulnerability is not in CISA KEV and no public POC is confirmed. Real-world risk is therefore low for most deployments; the meaningful threat scenario is a social-engineering campaign or supply-chain substitution of an archive. The I:L and A:L impacts are bounded to the bucket or filesystem path scope the user already has write access to - privilege escalation and confidentiality exposure are not in scope for this vulnerability.

An attacker crafts a zip archive containing a malicious entry named ../escaped.txt alongside legitimate-looking files and delivers it to a target user via email, file share, or CI pipeline artifact. The user runs rclone archive extract to unpack the archive into a cloud bucket subdirectory; because the pre-1.74.4 code passes the entry name directly to path.Join without sanitization, the traversal is resolved and escaped.txt is written as a sibling object one level above the intended prefix, potentially overwriting configuration files, index objects, or other data the user has write access to. No public POC is confirmed, but the Zip Slip technique is extensively documented and trivial to reproduce with standard archive tooling.