VDB-364543 · CVE-2026-45135 · GCVE-0-2026-45135

caddyserver caddy 2.11.1/2.11.2 FastCGI splitPos unicode encoding

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.7	$0-$5k	0.00

Summaryinfo

A vulnerability marked as problematic has been reported in caddyserver caddy. This vulnerability affects the function splitPos of the component FastCGI. This manipulation causes improper handling of unicode encoding. This vulnerability appears as CVE-2026-45135. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in caddyserver caddy. It has been declared as problematic. Affected by this vulnerability is the function splitPos of the component FastCGI. The manipulation with an unknown input leads to a improper handling of unicode encoding vulnerability. The CWE definition for the vulnerability is CWE-176. The product does not properly handle when an input contains Unicode encoding. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Caddy is an extensible server platform that uses TLS by default. From 2.7.0 until 2.11.3, the FastCGI transport's splitPos() in modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go misuses golang.org/x/text/search with search.IgnoreCase when the request path contains a non-ASCII byte. Two distinct flaws in that fallback let an attacker mislead Caddy's FastCGI splitting into treating a non-.php (or other configured split_path extension) file as a script. In any deployment where the attacker can place content into a file served via FastCGI (uploads, file storage, etc.), this can be escalated to remote code execution by crafting a URL whose path triggers either flaw. This vulnerability is fixed in 2.11.3.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-45135. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 2.11.3 eliminates this vulnerability.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

caddyserver

Name

caddy

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.8
VulDB Meta Temp Score: 6.7

VulDB Base Score: 5.6
VulDB Temp Score: 5.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.1
CNA Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper handling of unicode encoding
CWE: CWE-176 / CWE-172
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: caddy 2.11.3

Timelineinfo

05/19/2026 Advisory disclosed
05/19/2026 +0 days VulDB entry created
06/27/2026 +39 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-45135 (🔒)
GCVE (CVE): GCVE-0-2026-45135
GCVE (VulDB): GCVE-100-364543

Entryinfo

Created: 05/19/2026 07:29
Updated: 06/27/2026 19:43
Changes: 05/19/2026 07:29 (52), 06/27/2026 19:43 (12)
Complete: 🔍
Cache ID: 216::103