Vulnerability · Published Jun 23, 2026 · Assigned by GitHub_M

CVE-2026-52844Caddy: Windows `file_server` path authorization bypass via encoded backslash

High 7.5

In plain English

A high-severity path traversal in caddy from caddyserver. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 50.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:14	caddy	2.11.4-1	DEBIAN-CVE-2026-52844
Go	github.com/caddyserver/caddy	no fix listed	GHSA-qrp7-cvwr-j2c6
Go	github.com/caddyserver/caddy/v2	2.11.4	GHSA-qrp7-cvwr-j2c6
Go	github.com/caddyserver/caddy/v2	2.11.4	GO-2026-5595
Ubuntu:25.10	caddy	no fix listed	UBUNTU-CVE-2026-52844
Ubuntu:26.10	caddy	no fix listed	UBUNTU-CVE-2026-52844

Affected products (as reported)

Vendor	Product	Versions
caddyserver	caddy	< 2.11.4

Weakness: CWE-22, CWE-284 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

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