Caddy: FastCGI header normalization bypass in `forward_auth copy_headers`
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| caddyserver | caddy | affected |
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No data.
| Vendor | Product | Versions | ||||||||
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| Caddyserver | Caddy |
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4857-1 | caddy security update |
Debian DSA |
DSA-6429-1 | caddy security update |
Github GHSA |
GHSA-f59h-q822-g45g | Caddy: FastCGI header normalization bypass in `forward_auth copy_headers` |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.445% probability within 30 days)
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threat_severity
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threat_severity
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ssvc
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Caddyserver
Caddyserver caddy |
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Caddyserver
Caddyserver caddy |
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| Description | Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, forward_auth copy_headers deletes the exact client-supplied identity header before copying the trusted value from the auth gateway. But when the request later goes through php_fastcgi, Caddy normalizes HTTP headers into CGI variables by replacing - with _. This lets a client send an underscore alias that survives the forward_auth delete step but becomes the same PHP/FastCGI variable. Result: a remote client can inject or sometimes override identity/group headers trusted by PHP/FastCGI applications behind Caddy. This vulnerability is fixed in 2.11.4. | |
| Title | Caddy: FastCGI header normalization bypass in `forward_auth copy_headers` | |
| Weaknesses | CWE-287 CWE-290 CWE-444 |
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| Metrics |
cvssV3_1
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