caddyserver caddy 2.11.1 forward_auth copy_headers injection

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in caddyserver caddy. Affected by this issue is the function copy_headers of the component forward_auth. Executing a manipulation can lead to injection. This vulnerability is handled as CVE-2026-30851. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in caddyserver caddy and classified as critical. This vulnerability affects the function copy_headers of the component forward_auth. The manipulation with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-30851. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1055.

The vulnerability scanner Nessus provides a plugin with the ID 301667 (Linux Distros Unpatched Vulnerability : CVE-2026-30851), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.11.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (301667). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.6

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 8.8
NVD Vector: 🔒

CNA Base Score: 8.1
CNA Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Injection
CWE: CWE-74 / CWE-707 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 301667
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-30851

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: caddy 2.11.2

Timelineinfo

03/07/2026 Advisory disclosed
03/07/2026 +0 days VulDB entry created
03/12/2026 +5 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-30851 (🔒)
GCVE (CVE): GCVE-0-2026-30851
GCVE (VulDB): GCVE-100-349636

Entryinfo

Created: 03/07/2026 09:32
Updated: 03/12/2026 14:39
Changes: 03/07/2026 09:32 (53), 03/08/2026 15:36 (12), 03/11/2026 00:41 (2), 03/12/2026 14:39 (12)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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