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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| caddyserver | caddy | < 2.11.4 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | caddy | 2.11.4-1 | — |
| Debian 13 | caddy | 2.6.2-12+deb13u1 | — |
| Debian 12 | caddy | 2.6.2-5+deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | caddy | No fix yet | — |
| Ubuntu 25.10 | caddy | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | caddy | No fix yet | — |
| Ubuntu Pro 24.04 LTS | caddy | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | govulncheck-vulndb | 0.0.20260727T201416-160000.1.1 | SUSE-SU-2026:23227-1, SUSE-SU-2026:23216-1 |
| SLES 16.0 | govulncheck-vulndb | 0.0.20260727T201416-160000.1.1 | SUSE-SU-2026:23227-1, SUSE-SU-2026:23216-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260727T201416-160000.1.1 | openSUSE-SU-2026:21551-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/caddyserver/caddy | <= 1.0.5 | — | GHSA-vcc4-2c75-vc9v |
| Go | github.com/caddyserver/caddy/v2 | < 2.11.4 | 2.11.4 | GHSA-vcc4-2c75-vc9v |
Advisories 3
- SUSE-SU-2026:23227-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Aug 27, 2026
- SUSE-SU-2026:23216-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Aug 27, 2026
- openSUSE-SU-2026:21551-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Aug 12, 2026