CVAT EUVD-2026-52892

Exploitation requires one of two conditions: (a) the attacker already has write access to a cloud storage bucket (e.g., AWS S3, Azure Blob, Google Cloud Storage) that has been integrated into the CVAT instance, allowing them to plant a malicious manifest; or (b) the attacker holds CVAT account permissions sufficient to add new cloud storage integrations, enabling them to register an attacker-controlled bucket. The CVSS PR:L confirms that some level of authenticated CVAT access is required - fully external, unauthenticated attackers cannot exploit this. Exploitation is further limited by the need for server-side processing to occur (backup import, media ingestion, or cache refresh must be triggered for the traversal path to be written). Deployments where cloud storage write access and CVAT cloud storage configuration are restricted to highly trusted administrators have significantly reduced exposure.

The CVSS 4.0 score of 7.1 with vector AV:N/AC:L/AT:N/PR:L/UI:N/VI:H accurately captures the real-world risk profile: the attack is network-accessible with low complexity and requires no user interaction, but does require low-privileged access - specifically, the ability to write to an attached cloud storage or to configure a new one. This prerequisite meaningfully limits the exposed population to authenticated, partially-trusted CVAT collaborators or compromised cloud storage credentials rather than fully external attackers. The integrity impact is rated High because overwriting arbitrary server files can yield secondary effects such as code execution (overwriting application files, cron jobs, or configuration), making the realistic severity higher than a simple file-corruption scenario. No EPSS data was provided in the input, and no CISA KEV listing exists, so active exploitation cannot be confirmed. The lack of a public POC and the non-trivial prerequisite (cloud storage access) further moderate immediate priority, but the code-execution escalation potential warrants prompt patching for any CVAT deployment with untrusted collaborators or externally-accessible cloud storage buckets.

An attacker with write access to an S3 bucket linked to a CVAT instance uploads a crafted manifest file whose entries contain path traversal sequences such as '../../etc/cron.d/backdoor'. When a CVAT server process - such as backup import or cache population - reads this manifest and constructs destination paths using os.path.join without sanitization, it writes attacker-controlled file content to the traversed location outside the intended storage directory. Overwriting a cron entry or application configuration file in this manner could escalate the impact to remote code execution on the server. No public proof-of-concept has been identified at time of analysis.