What is the CVSS score of CVE-2026-27587?

CVE-2026-27587 has a CVSS 3.1 base score of 9.1 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. EPSS exploitation probability: 0.0%.

Which versions of TLS are affected by CVE-2026-27587?

A critical vulnerability in Caddy web servers (CVE-2026-27587) allows attackers to bypass path-based access controls through case-sensitivity mishandling in URL encoding, potentially exposing…. A patch is available.

Is there a public PoC exploit available for CVE-2026-27587?

Yes, a public proof-of-concept exploit is available for CVE-2026-27587. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-27587?

Within 24 hours: inventory all Caddy instances and their versions; disable or restrict HTTP path matchers containing percent-escape sequences if operationally feasible; enable enhanced logging on path-based access controls. Within 7 days: implement WAF rules to normalize and validate URL encoding before requests reach Caddy; segment affected systems from sensitive data stores; establish daily vulnerability scanning. Within 30 days: upgrade to Caddy 2.11.1 or later once available; conduct security audit of all path-based access control policies; perform penetration testing to validate remediation.

TLS CVE-2026-27587

CRITICAL

Improper Handling of Case Sensitivity (CWE-178)

2026-02-24 security-advisories@github.com

GHSA-g7pc-pc7g-h8jh

TLS Caddy Suse

9.1

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

9.1 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

SUSE

CRITICAL

qualitative

Primary rating from GitHub Advisory.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

PoC Detected

Feb 25, 2026 - 17:11 vuln.today

Public exploit code

CVE Published

Feb 24, 2026 - 17:29 nvd

CRITICAL 9.1

DescriptionGitHub Advisory

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP path request matcher is intended to be case-insensitive, but when the match pattern contains percent-escape sequences (%xx) it compares against the request's escaped path without lowercasing. An attacker can bypass path-based routing and any access controls attached to that route by changing the casing of the request path. Version 2.11.1 contains a fix for the issue.

AnalysisAI

Case sensitivity bypass in Caddy web server path matching before 2.11.1. HTTP path matchers can be bypassed using alternate casing on case-insensitive filesystems. PoC available.

Technical ContextAI

CWE-178 improper handling of case sensitivity. Caddy's path matcher is case-sensitive but the underlying filesystem may be case-insensitive, allowing access control bypass.

RemediationAI

Update to Caddy 2.11.1. Use case-insensitive matching or normalize request paths.

More in TLS

View all

CVE-2026-27180 CRITICAL Emergency POC

9.8 Feb 18

MajorDoMo home automation platform is vulnerable to unauthenticated remote code execution through supply chain compromis

CVE-2026-27944 CRITICAL Act Now POC

9.8 Mar 05

Unauthenticated backup download and RCE in Nginx UI before 2.3.3. EPSS 1.0%. PoC available.

CVE-2026-27590 CRITICAL Act Now POC

9.8 Feb 24

FastCGI path splitting vulnerability in Caddy before 2.11.1 allows request smuggling or path confusion when proxying to

CVE-2026-27586 CRITICAL Act Now POC

9.1 Feb 24

TLS error swallowing in Caddy web server before 2.11.1 allows bypassing client certificate authentication. Errors in Cli

CVE-2026-27588 CRITICAL Act Now POC

9.1 Feb 24

Host header case sensitivity bypass in Caddy before 2.11.1. Virtual host routing can be bypassed by using alternate casi

CVE-2026-25160 CRITICAL Act Now POC

9.1 Feb 04

Alist file manager has an improper certificate validation vulnerability allowing MITM attacks that could compromise file

CVE-2026-30851 HIGH This Week POC

8.1 Mar 07

Caddy versions 2.10.0 through 2.11.1 fail to strip client-supplied headers in the forward_auth copy_headers directive, e

CVE-2022-40620 HIGH This Week POC

7.7 Jan 28

FunJSQ, a third-party module integrated on some NETGEAR routers and Orbi WiFi Systems, does not properly validate TLS ce

CVE-2026-30852 HIGH This Week POC

7.5 Mar 07

Caddy versions 2.7.5 through 2.11.1 contain a template injection vulnerability in the vars_regexp matcher that allows re

CVE-2026-25961 HIGH This Week POC

7.5 Feb 09

SumatraPDF versions 3.5.0 through 3.5.2 fail to validate TLS certificates during software updates and execute installers

CVE-2025-68133 HIGH This Week POC

7.4 Jan 21

EVerest is an EV charging software stack. In versions 2025.9.0 and below, an attacker can exhaust the operating system's

CVE-2026-27585 MEDIUM This Month POC

6.5 Feb 24

Caddy versions prior to 2.11.1 fail to sanitize backslashes in file path matching, allowing attackers to bypass path-bas

Same weakness CWE-178 – Improper Handling of Case Sensitivity

View all

CVE-2025-27636 MEDIUM POC

5.6

CVE-2021-24347 HIGH POC

8.8

CVE-2024-5699 CRITICAL POC

9.8

CVE-2023-3545 CRITICAL POC

9.8

CVE-2018-9845 CRITICAL POC

9.8

CVE-2026-27588 CRITICAL POC

9.1

CVE-2020-12812 CRITICAL

9.8

CVE-2024-6866 HIGH POC

7.5

Vendor StatusVendor

SUSE

Severity: Critical

Product	Status
openSUSE Leap 15.6	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP5	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP6	Fixed
openSUSE Leap 15.5	Fixed

CVE-2026-27587 vulnerability details – vuln.today

Back

TLS CVE-2026-27587

Severity by source

CVSS VectorGitHub Advisory

Lifecycle Timeline

DescriptionGitHub Advisory

AnalysisAI

Technical ContextAI

RemediationAI

More in TLS

Same weakness CWE-178 – Improper Handling of Case Sensitivity

Vendor StatusVendor

SUSE

Share

External POC / Exploit Code