Is CVE-2026-52845 in the CISA KEV catalog?

No. CVE-2026-52845 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-52845?

CVE-2026-52845 has a CVSS v3 base score of 8.1 (HIGH).

What is the EPSS score for CVE-2026-52845?

CVE-2026-52845 has an EPSS score of 0.25% (16th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-52845

HIGH

8.1

CVSS v3

NVD

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.

CWE-287Improper Authentication CWE-290 CWE-444

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Exploit Intelligence

0.25%probability of exploitation in 30 days

16thpercentile

Low risk: more likely to be exploited than 16% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-30.