# 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.

- Web page: https://patchblox.com/security/fix/windows-app/golang.go-1.26.3
- Platform: Windows apps
- Released: May 7, 2026
- Priority: High (Closes CVE-2026-33811, high severity)
- CVEs: 11, exploited: 0, on CISA KEV: 0
- Superseded by: [Go Programming Language 1.27.4](https://patchblox.com/security/data/product/windows-app/go-programming-language.md), the latest version, which also fixes every CVE listed here

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Go Programming Language](https://patchblox.com/security/data/product/windows-app/go-programming-language.md) |  | 1.26.3 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-33811](https://patchblox.com/security/data/cve/CVE-2026-33811.md) | High | Crash when handling long CNAME response in net | 8.8 | 0.0088 |  |
| [CVE-2026-33814](https://patchblox.com/security/data/cve/CVE-2026-33814.md) | High | 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 |  |
| [CVE-2026-42499](https://patchblox.com/security/data/cve/CVE-2026-42499.md) | High | Quadratic string concatenation in consumePhrase in net/mail | 8.8 | 0.0080 |  |
| [CVE-2026-39820](https://patchblox.com/security/data/cve/CVE-2026-39820.md) | High | Quadratic string concatentation in consumeComment in net/mail | 8.8 | 0.0078 |  |
| [CVE-2026-39836](https://patchblox.com/security/data/cve/CVE-2026-39836.md) | High | Panic in Dial and LookupPort when handling NUL byte on Windows in net | 7.5 | 0.0063 |  |
| [CVE-2026-39825](https://patchblox.com/security/data/cve/CVE-2026-39825.md) | High | ReverseProxy forwards queries with more than urlmaxqueryparams parameters in net/http/httputil | 7.5 | 0.0039 |  |
| [CVE-2026-39826](https://patchblox.com/security/data/cve/CVE-2026-39826.md) | High | Escaper bypass leads to XSS in html/template | 7.5 | 0.0037 |  |
| [CVE-2026-39823](https://patchblox.com/security/data/cve/CVE-2026-39823.md) | High | Bypass of meta content URL escaping causes XSS in html/template | 7.5 | 0.0031 |  |
| [CVE-2026-42501](https://patchblox.com/security/data/cve/CVE-2026-42501.md) | High | Malicious module proxy can bypass checksum database in cmd/go | 7.5 | 0.0023 |  |
| [CVE-2026-39819](https://patchblox.com/security/data/cve/CVE-2026-39819.md) | High | Invoking "go bug" follows symlinks in predictable temporary filenames in cmd/go | 7.5 | 0.0018 |  |
| [CVE-2026-39817](https://patchblox.com/security/data/cve/CVE-2026-39817.md) | High | Invoking "go tool pack" does not sanitize output paths in cmd/go | 7.5 | 0.0017 |  |

---

Data as of 2026-11-11T13:47:35Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.