CVE-2026-30851 — Improper Authentication in Caddyserver Caddy V2

CWE-287 — Improper AuthenticationCWE-345 — Insufficient Verification of Data Authenticity8 documents6 sources
Severity
8.8HIGHNVD
CNA8.1
EPSS
0.0%
top 94.84%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
3
Github.com Caddyserver Caddy V2Github.com Caddyserver Caddy V2 Modules Caddyhttp ReverseproxyCaddyserver Caddy
Timeline
PublishedMar 7
Latest updateMar 10

Description

Caddy is an extensible server platform that uses TLS by default. From version 2.10.0 to before version 2.11.2, forward_auth copy_headers does not strip client-supplied headers, allowing identity injection and privilege escalation. This issue has been patched in version 2.11.2.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitability: 2.8 | Impact: 5.9

Affected Packages4 packages

▶NVDcaddyserver/caddy2.10.0 — 2.11.2
▶Gogithub.com/caddyserver_caddy_v22.10.0 — 2.11.2
▶CVEListV5caddyserver/caddy>= 2.10.0, < 2.11.2

Patches

Patch: github.com ↗Patch: github.com ↗Patch: github.com ↗

🔴Vulnerability Details

5
OSV
Caddy forward_auth copy_headers allows Identity Injection and Privilege Escalation in github.com/caddyserver/caddy↗2026-03-10
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OSV
CVE-2026-30851: Caddy is an extensible server platform that uses TLS by default↗2026-03-07
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CVEList
Caddy forward_auth copy_headers Does Not Strip Client-Supplied Headers, Allowing Identity Injection and Privilege Escalation↗2026-03-07
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GHSA
Caddy forward_auth copy_headers Does Not Strip Client-Supplied Headers, Allowing Identity Injection and Privilege Escalation↗2026-03-06
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OSV
Caddy forward_auth copy_headers Does Not Strip Client-Supplied Headers, Allowing Identity Injection and Privilege Escalation↗2026-03-06
▶

📋Vendor Advisories

1
Debian
CVE-2026-30851: caddy - Caddy is an extensible server platform that uses TLS by default. From version 2....↗2026
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🕵️Threat Intelligence

1
Wiz
CVE-2026-30851 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-30851 — Improper Authentication | cvebase