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CVE-2026-45692· NVD / CVE Program· CNA GitHub_M

Caddy: Remote Admin Authorization Bypass in `/config` API via Array Index Normalization

Caddy is an extensible server platform that uses TLS by default. From 2.4.0 until 2.11.3, the authorization layer and the /config traversal layer do not agree on what object the path refers to. In this case, a path authorized for one config object is accepted, but then resolves to a different config object during traversal. This happens because the authorization layer uses string prefix matching and the /config traversal layer parses array indices numerically using strconv.Atoi(). This vulnerability is fixed in 2.11.3.

LowCVSS 3.8 · v3.1—No exploit Fix available
Published
Jun 23, 2026
Updated
Jun 26, 2026
EPSS
0.2% · 14th percentile
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Report tools

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Action score

15

Monitor

Low priority for now.

CVSS
15 / 40 · 3.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
3.8
CNA · GitHub_M
5.4
1.6 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
caddyservercaddy

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • caddyserver caddy2.4.0 and later · before 2.11.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • caddyserver caddy

    • >= 2.4.0, < 2.11.3affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12caddyall versions—
Debian:13caddybefore 2.6.2-12+deb13u12.6.2-12+deb13u1
Debian:14caddybefore 2.11.4-12.11.4-1
Gogithub.com/caddyserver/caddy/v2from 2.4.0 · before 2.11.32.11.3

Same product

caddyserver: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-21246Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostM
    40Plan
  • CVE-2026-30851Caddy forward_auth copy_headers Does Not Strip Client-Supplied Headers, Allowing Identity Injection and Privilege Escalation
    35Monitor
  • CVE-2026-27590Caddy: Unicode case-folding length expansion causes incorrect split_path index (SCRIPT_NAME/PATH_INFO confusion) in FastCGI transport
    35Monitor
  • CVE-2026-27586Caddy's mTLS client authentication silently fails open when CA certificate file is missing or malformed
    35Monitor
  • CVE-2026-52845Caddy: FastCGI header normalization bypass in `forward_auth copy_headers`
    32Monitor
  • CVE-2026-45135Caddy: Unsafe Unicode Handling in FastCGI splitPos Allows Execution of Non-PHP Files
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
caddyserver caddy2.11.3 · descriptionVendor (CNA)
debian:caddy2.6.2-12+deb13u1 · Debian:13Package registry (OSV)
Go:github.com/caddyserver/caddy/v22.11.3Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • Administrator privileges are required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-187 · Partial String Comparison

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

  1. Fix✗ → ✓

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