Cyber Resilience

CVE-2026-27589

CSRF in Caddyserver Caddy ≤ 2.11.1

Public PoCCSRF
Published
24 February 2026
Modified
25 February 2026
Patch / advisory
View advisory
CVSS Score v4 6.9
Click a component to see what it means
Raw vectorCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0017 6th percentile
Risk Priority 39 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-27589 is a medium-severity CSRF (CWE-352) vulnerability in Caddyserver Caddy. Its CVSS base score is 6.9 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SC-23 (Session Authenticity) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, the local caddy admin API (default listen `127.0.0.1:2019`) exposes a state-changing `POST /load` endpoint that replaces the entire running configuration. When origin enforcement is not…

more

enabled (`enforce_origin` not configured), the admin endpoint accepts cross-origin requests (e.g., from attacker-controlled web content in a victim browser) and applies an attacker-supplied JSON config. This can change the admin listener settings and alter HTTP server behavior without user intent. Version 2.11.1 contains a fix for the issue.

CWE(s)
CWE-352

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-41344Shared CWE-352
CVE-2025-30862Shared CWE-352
CVE-2024-39063Shared CWE-352
CVE-2023-23704Shared CWE-352
CVE-2024-39157Shared CWE-352
CVE-2024-54436Shared CWE-352
CVE-2025-25123Shared CWE-352
CVE-2023-28989Shared CWE-352
CVE-2023-46092Shared CWE-352
CVE-2024-27968Shared CWE-352

Affected Assets

caddyserver
caddy
≤ 2.11.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V3.3.2
  • V3.5.1
  • V10.2.1

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement partial match

Access enforcement requires verifying that state-changing requests originate from the authenticated user rather than a forged cross-site source.

SC-23 Session Authenticity partial match

Protecting session authenticity prevents attackers from replaying or forging authenticated requests via the victim's browser.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require anti-CSRF controls such as tokens or SameSite attributes.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.23 Web filtering partial match
mitigates

By denying access to phishing or malicious sites, the control lowers the likelihood that a user will be tricked into submitting a forged request that performs an unintended action on another site.

References