CVE-2026-52844

Caddy: Windows `file_server` path authorization bypass via encoded backslash

HIGH
7.5
CVSS Score
Published: June 23, 2026 at 05:50 PM UTC
Updated: October 25, 2026 at 11:10 PM UTC
1 product affected across 1 vendorCaddy· also runs on 1 platform

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.11.4
Affected range stops below 2.11.4, so it looks safe — our inference, not a vendor statement
microsoft-windows (environment)

Runs on — not affected

The affected product only carries this flaw when running on these platforms. The platforms themselves are not vulnerable.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

x_refsource_CONFIRMThird Party AdvisoryExploit
Source: cverecord
https://github.com/caddyserver/caddy/security/advisories/GHSA-qrp7-cvwr-j2c6

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-22CWE-284

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