CVE-2026-52846
Caddy: stripHTML template function bypass
Description
Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, Caddy’s stripHTML template function cannot reliably remove all HTML tags from input strings. Certain malformed HTML, such as <<>img src=x onerror=alert()>, can bypass the tag-stripping logic, potentially leaving dangerous content in the output if it is later rendered as HTML. This may allow client-side XSS in cases where untrusted strings are rendered unsafely. This vulnerability is fixed in 2.11.4.
INFO
Published Date :
June 23, 2026, 6:18 p.m.
Last Modified :
June 29, 2026, 7:08 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Caddy to version 2.11.4 or later.
- Verify the stripHTML function behavior.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-52846.
| URL | Resource |
|---|---|
| https://github.com/caddyserver/caddy/security/advisories/GHSA-vcc4-2c75-vc9v | Exploit Third Party Advisory |
| https://github.com/caddyserver/caddy/security/advisories/GHSA-vcc4-2c75-vc9v | Exploit Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-52846 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-52846
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-52846 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-52846 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 29, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:* versions up to (excluding) 2.11.4 Added Reference Type GitHub, Inc.: https://github.com/caddyserver/caddy/security/advisories/GHSA-vcc4-2c75-vc9v Types: Exploit, Third Party Advisory Added Reference Type CISA-ADP: https://github.com/caddyserver/caddy/security/advisories/GHSA-vcc4-2c75-vc9v Types: Exploit, Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 25, 2026
Action Type Old Value New Value Added Reference https://github.com/caddyserver/caddy/security/advisories/GHSA-vcc4-2c75-vc9v Added SSVC {'id': 'CVE-2026-52846', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-25T12:42:12.083385Z'} -
New CVE Received by [email protected]
Jun. 23, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'caddyserver', 'product': 'caddy', 'versions': [{'status': 'affected', 'version': '< 2.11.4'}]}] Added Description Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, Caddy’s stripHTML template function cannot reliably remove all HTML tags from input strings. Certain malformed HTML, such as <<>img src=x onerror=alert()>, can bypass the tag-stripping logic, potentially leaving dangerous content in the output if it is later rendered as HTML. This may allow client-side XSS in cases where untrusted strings are rendered unsafely. This vulnerability is fixed in 2.11.4. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N Added CWE CWE-116 Added Reference https://github.com/caddyserver/caddy/security/advisories/GHSA-vcc4-2c75-vc9v