CVE-2026-78660
HTTP/2 transport accepts malformed framing-related headers in net/http
HIGH 7.5
At a glance
- Source
- NVD
- EPSS
- EPSS 0.43 % · percentile 37 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Go
- NVD status
- Awaiting Analysis
Description
Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing. However, this makes it possible for our HTTP/2 implementation to forward responses containing such headers to an HTTP/1 client when acting as a reverse proxy. If the HTTP/1 client also does not behave strictly enough, this can result in response smuggling.
Weaknesses (CWE)
- CWE-444 — Inconsistent Interpretation of HTTP Requests
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | CISA-ADP |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
Advisories
- GO-2026-6610 — HTTP/2 transport accepts malformed framing-related headers in net/http
European references
- ENISA EUVD · EUVD-2026-95425
- GCVE · GCVE-0-2026-78660
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| Go standard library · net/http | affected 0 < 1.26.9 |
| Go standard library · net/http/internal/http2 | affected 1.27.0-0 < 1.27.2 |
| golang.org/x/net · golang.org/x/net/http2 | affected 0 < 0.60.0 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |