# CVE-2026-77281: caddy: Caddy is an extensible server platform that uses TLS by default

CVE-2026-77281 is fixed in caddy on 1 platform, first by DEBIAN-CVE-2026-77281, released September 20, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-77281
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | caddy Debian 12.15 (bookworm) | 2.6.2-5+deb12u1 | [DEBIAN-CVE-2026-77281](https://patchblox.com/security/data/fix/linux/debian-cve-2026-77281.md) | Sep 20, 2026 |
| Linux | caddy Debian 14 | 2.11.4-1 | [DEBIAN-CVE-2026-77281](https://patchblox.com/security/data/fix/linux/debian-cve-2026-77281.md) | Sep 20, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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