Caddy: rewrite placeholder re-expansion

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-77281
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 21:17:37 UTC
Updated2026-09-24 21:16:28 UTC
DescriptionCaddy 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

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

EPSS: 0.004910000 probability, percentile 0.396300000 (date 2026-09-25)

Problem Types: CWE-94 | CWE-178 | CWE-770 | CWE-94 CWE-94: Improper Control of Generation of Code ('Code Injection') | CWE-178 CWE-178: Improper Handling of Case Sensitivity | CWE-770 CWE-770: Allocation of Resources Without Limits or Throttling

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
Low

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Caddyserver Caddy affected < 2.11.4 Not specified

References

ReferenceSourceLinkTags
github.com/caddyserver/caddy/releases/tag/v2.11.4 [email protected] github.com
github.com/caddyserver/caddy/pull/7761 [email protected] github.com
github.com/caddyserver/caddy/commit/176b043b0104cee3f894023cd5a598ac29e4... [email protected] github.com
github.com/caddyserver/caddy/security/advisories/GHSA-j8px-rmrx-76h9 [email protected] github.com
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