GHSA-5r3v-vc8m-m96g: github.com/caddyserver/caddy/v2 (CVE-2026-27590)

Caddy: Unicode case-folding length expansion causes incorrect split_path index in FastCGI transport

CVSS 8.9 HighEPSS 0.0061 · 49th percentile

Published by the GitHub Advisory Database at 24 Feb 2026, 20:39 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
github.com/caddyserver/caddy/v2	Go	<2.11.1	2.11.1

Identifiers

GHSA-5r3v-vc8m-m96g · CVE-2026-27590 · GO-2026-4536

Weakness (CWE)

CWE-20 · CWE-180

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
8.9	High	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0061, the 49th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the GitHub Advisory Database, published 24 Feb 2026. New records show when each source confirmed them.

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.