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Findings

CVE-2026-78660

HTTP/2 transport accepts malformed framing-related headers in net/http

Published Oct 8, 2026 · corrected/updated Oct 16, 2026 · evidence confidence high

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.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-78660 is a high public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: golang (0 → 1.26.9); golang.org/x/net (0 → 0.60.0); stdlib (0 → 1.26.9); stdlib (1.27.0-0 → 1.27.2). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: no CVSS/EPSS yet. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: cve_org, osv, osv. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in the CISA KEV catalog.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 8, 2026 · OSV.dev

    Detected

    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

  2. Oct 16, 2026 · OSV.dev

    Fix available

    stdlib fixed in 1.26.9; stdlib fixed in 1.27.2; golang.org/x/net fixed in 0.60.0

  3. Oct 16, 2026 · OSV.dev

    Fix available

    stdlib fixed in 1.26.9

  4. Oct 16, 2026 · OSV.dev

    Fix available

    stdlib fixed in 1.27.2

  5. Oct 16, 2026 · OSV.dev

    Fix available

    golang.org/x/net fixed in 0.60.0

  6. Oct 16, 2026 · OSV.dev

    Fix available

    golang fixed in 1.26.9

  7. Oct 16, 2026 · OSV.dev

    Fix available

    golang fixed in 1.26.9

  8. Oct 16, 2026 · OSV.dev

    Updated

    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

Affected

  • Bitnami golang0 → 1.26.9
  • Go golang.org/x/net0 → 0.60.0
  • Go stdlib0 → 1.26.9
  • Go stdlib1.27.0-0 → 1.27.2

Sources

  • CVE.orgVulnerability recordCVE-2026-78660

    Official CVE identifier

    cve.org
  • OSV.devPackage advisoryBIT-golang-2026-78660

    HTTP/2 transport accepts malformed framing-related headers in net/http

    osv.dev
  • OSV.devPackage advisoryGO-2026-6610

    HTTP/2 transport accepts malformed framing-related headers in net/http

    osv.dev

References