Caddy is an extensible server platform that uses TLS by default. In version 2.11.3 and earlier, three configuration-dependent weaknesses affect the handler and placeholder layer. In modules/caddyhttp/rewrite/rewrite.go, Rewrite.Rewrite() can pass attacker-controlled replacement bytes through buildQueryString for a second placeholder expansion when a rewrite URI ends with a literal question mark, allowing injected environment or request-variable placeholders to disclose data and, when the file provider is registered, allowing injected file placeholders to disclose readable files. The issue is fixed in version 2.11.4.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-j8px-rmrx-76h9 Caddy: rewrite placeholder re-expansion, unbounded body buffer DoS, and fileHidden case-sensitivity bypass
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Sun, 20 Sep 2026 03:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 18 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Caddyserver
Caddyserver caddy
Vendors & Products Caddyserver
Caddyserver caddy

Thu, 17 Sep 2026 21:15:00 +0000

Type Values Removed Values Added
Description Caddy is an extensible server platform that uses TLS by default. In version 2.11.3 and earlier, three configuration-dependent weaknesses affect the handler and placeholder layer. In modules/caddyhttp/rewrite/rewrite.go, Rewrite.Rewrite() can pass attacker-controlled replacement bytes through buildQueryString for a second placeholder expansion when a rewrite URI ends with a literal question mark, allowing injected environment or request-variable placeholders to disclose data and, when the file provider is registered, allowing injected file placeholders to disclose readable files. The issue is fixed in version 2.11.4.
Title Caddy: rewrite placeholder re-expansion
Weaknesses CWE-178
CWE-770
CWE-94
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-18T14:43:34.818Z

Reserved: 2026-08-20T19:14:21.331Z

Link: CVE-2026-77281

cve-icon Vulnrichment

Updated: 2026-09-18T14:39:57.835Z

cve-icon NVD

Status : Received

Published: 2026-09-17T21:17:37.890

Modified: 2026-09-18T15:17:12.747

Link: CVE-2026-77281

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-18T23:45:15Z

Weaknesses