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Caddy CVE-2026-92700

| EUVDEUVD-2026-85515 MEDIUM
Improper Handling of Case Sensitivity (CWE-178)
2026-09-23 GitHub_M
6.3
CVSS 4.0 · Vendor: GitHub_M
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Identify Caddy file_server with hide rules
  2. Delivery
    Request hidden path with altered case
  3. Exploit
    Case-sensitive filepath.Match fails to match
  4. Execution
    Server serves intended-hidden file
  5. Impact
    Disclose secrets/config contents

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Case sensitivity handling
Exploitation Conditions

Requires Caddy's file_server handler configured with a hide directive AND the files being served from a case-insensitive filesystem (Windows, default macOS/APFS) or a scenario where mixed-case path variants of the same file coexist. Exploitation is unauthenticated and remote, but the bypass does NOT apply on standard case-sensitive Linux filesystems (ext4/xfs) - which is the most common Caddy production platform - so this AT:P attack requirement significantly limits real-world exposure. Impact is limited to disclosure of files the operator intended to hide; no integrity or availability impact.

Impact

This is a genuine but modest-severity information disclosure issue, not a top-tier priority. The vendor CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N/VC:L, score 6.3) indicates a network-reachable, unauthenticated flaw but with an attack requirement (AT:P) and only Low confidentiality impact and no integrity/availability impact - consistent with a hide-rule bypass that leaks file contents rather than granting code execution. The AT:P requirement is the key nuance: exploitation is gated on the underlying filesystem being case-insensitive (Windows/macOS default) or on mixed-case paths coexisting, so on typical Linux/ext4 production deployments the bypass generally does not apply. No EPSS score, no CISA KEV listing, and no working POC for THIS specific issue were provided (the reproduction code in the advisory demonstrates a DIFFERENT bundled vulnerability, the rewrite double-expansion CWE-94 issue, not the fileHidden bypass). Net: no public exploit identified for this issue at time of analysis and no evidence of active exploitation - treat as a low-to-medium remediation priority, prioritized higher only where Caddy serves files from a case-insensitive filesystem and relies on the hide directive to protect secrets such as .env or config files.

Exploit ScenarioDerived

An operator runs Caddy's file_server with a hide directive (e.g. hiding .env or a config file) on a case-insensitive filesystem such as Windows or default macOS. A remote unauthenticated attacker requests the same file using a case variant (e.g. /.ENV or /Config.json), which does not match the case-sensitive filepath.Match hide check, and the server returns the intended-hidden file's contents. No POC for this specific issue is public; the advisory's reproduction code covers a separate bundled bug.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 23, 2026

Unauthenticated file disclosure in Caddy 2.11.3 and earlier allows remote attackers to bypass the file_server hide directive by requesting case variants of hidden files. This affects deployments on case-insensitive filesystems (Windows, default macOS/APFS) or where mixed-case path variants coexist; standard case-sensitive Linux filesystems (ext4/xfs) are not affected. Impact is limited to information disclosure of files intended to be hidden, with no integrity or availability impact. Caddy 2.11.4 contains the fix. No public exploit code or active exploitation has been identified at time of analysis.

RemediationAI

Upgrade to Caddy 2.11.4 or later. The fix is available via GitHub PR https://github.com/caddyserver/caddy/pull/7761 and commit 176b043b0104cee3f894023cd5a598ac29e404bb. If upgrade is not immediately possible, do not rely on the hide directive as a security boundary; move sensitive files outside the web root, enforce OS-level file permissions, or use a separate case-sensitive filesystem for served content. Note that simply adding mixed-case hide patterns is unreliable because the underlying filesystem determines resolution. These compensating controls require operational changes and do not fully replicate the patch.

Affected VersionsENISA

caddy ≤ 2.11.3

Affected Packages

go github.com/caddyserver/caddy/v2 fix: 2.11.4
euvd caddy no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in go, euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The vulnerability is in Caddy's file_server handler, specifically the fileHidden() function in modules/caddyhttp/fileserver/staticfiles.go. Caddy uses filepath.Match to compare request paths against configured hide patterns, but filepath.Match performs case-sensitive matching. On case-insensitive filesystems (e.g., Windows, default macOS/APFS), or when a server hosts both mixed-case variants of the same file, an attacker can request a file using a different case (e.g., Secret.txt vs secret.txt) and evade the hide rule. This is classified as CWE-178 (Improper Handling of Case Sensitivity). The issue affects all versions of caddyserver:caddy up to and including 2.11.3 as indicated by the CPE cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:*. The vendor advisory (GHSA-j8px-rmrx-76h9) bundles this with two other unrelated issues in the handler/placeholder layer, but CVE-2026-92700 specifically covers the fileHidden case-sensitivity bypass. The assessed CVSS 3.1 vector is AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N, reflecting the requirement for a case-insensitive filesystem or mixed-case path scenario. The fix is included in Caddy 2.11.4.

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Severity by source

Vendor (GitHub_M) PRIMARY 6.3 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
vuln.today AI 3.7 LOW

Remote unauthenticated (AV:N/PR:N) but AC:H because success depends on a case-insensitive filesystem/mixed-case condition; only file contents leak, so C:L and I/A:N.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
SUSE MEDIUM

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

Caddy is an extensible server platform that uses TLS by default. In version 2.11.3 and earlier, in modules/caddyhttp/fileserver/staticfiles.go, fileHidden() uses case-sensitive filepath.Match checks, so case variants can bypass hide rules on case-insensitive filesystems or when mixed-case paths coexist and expose files intended to be hidden.

Threat Intelligence Overview

EPSS Score
0.4%
Top 67% exploitable
Prevalence
Medium
popular Go web server/reverse proxy, common but far behind nginx/Apache
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment Vendor GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
Poc
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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