Go Programming Language 1.26.3
Go Programming Language 1.26.3, released May 7, 2026, fixes 11 CVEs in Go Programming Language. None of them is reported as exploited. Patch Radar priority: High. The latest Go Programming Language is 1.27.4, which also fixes every one of these CVEs.
Superseded. The latest Go Programming Language is 1.27.4, which also fixes every CVE on this page. Install that instead.
Priority of the 11 CVEs
Applies to
| Product | Version |
|---|---|
| Go Programming Language | 1.26.3 |
CVEs this fix closes
| Priority | CVE | Title | CVSS | EPSS | Exploitation |
|---|---|---|---|---|---|
| High | CVE-2026-33811 | Crash when handling long CNAME response in net | 8.8 | 0.0088 | None reported |
| High | CVE-2026-33814 | Infinite loop in HTTP/2 transport when given bad SETTINGS_MAX_FRAME_SIZE in net/http/internal/http2 in golang.org/x/net | 7.5 | 0.0084 | None reported |
| High | CVE-2026-42499 | Quadratic string concatenation in consumePhrase in net/mail | 8.8 | 0.0080 | None reported |
| High | CVE-2026-39820 | Quadratic string concatentation in consumeComment in net/mail | 8.8 | 0.0078 | None reported |
| High | CVE-2026-39836 | Panic in Dial and LookupPort when handling NUL byte on Windows in net | 7.5 | 0.0063 | None reported |
| High | CVE-2026-39825 | ReverseProxy forwards queries with more than urlmaxqueryparams parameters in net/http/httputil | 7.5 | 0.0039 | None reported |
| High | CVE-2026-39826 | Escaper bypass leads to XSS in html/template | 7.5 | 0.0037 | None reported |
| High | CVE-2026-39823 | Bypass of meta content URL escaping causes XSS in html/template | 7.5 | 0.0031 | None reported |
| High | CVE-2026-42501 | Malicious module proxy can bypass checksum database in cmd/go | 7.5 | 0.0023 | None reported |
| High | CVE-2026-39819 | Invoking "go bug" follows symlinks in predictable temporary filenames in cmd/go | 7.5 | 0.0018 | None reported |
| High | CVE-2026-39817 | Invoking "go tool pack" does not sanitize output paths in cmd/go | 7.5 | 0.0017 | None reported |
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