Caddy: stripHTML template function bypass_CVE-2026-52846

4.2 / 10

MEDIUM

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

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.

Basic Information

ID CVE-2026-52846

Source GitHub_M

Published Jun 23, 2026 at 17:47

Affected Product

Vendor caddyserver

Product caddy

Version < 2.11.4

Affected Versions caddyserver caddy < 2.11.4

CWE Classification

CWE-116

References

github.com /caddyserver/caddy/security/advisories/GHSA-vcc4-2c75-vc9v

{
    "lastseen": "",
    "description": "Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, Caddy\u2019s 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.",
    "published": "2026-06-23T17:47:30.387Z",
    "modified": "2026-06-23T17:47:30.387Z",
    "type": "cve",
    "title": "Caddy: stripHTML template function bypass",
    "source": "GitHub_M",
    "references": "https://github.com/caddyserver/caddy/security/advisories/GHSA-vcc4-2c75-vc9v",
    "id": "CVE-2026-52846",
    "bulletinFamily": "",
    "cwe": [
        "CWE-116"
    ],
    "cvelist": null,
    "sourceData": "caddyserver caddy < 2.11.4",
    "sourceHref": "",
    "cvss": {
        "score": 4.2,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "caddy",
    "version": "< 2.11.4",
    "vendor": "caddyserver",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}