---
id: "CVE-2026-126405"
page: "https://infrastack.ai/live/CVE-2026-126405"
kind: "vulnerability"
aliases: ["CVE-2026-126405"]
title: "Coder: unbounded Web Push response read lets any user crash the server"
severity: "high"
cvss: 7.1
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["coder", "infrastructure", "kubernetes", "self-hosted"]
not_affected_if: ["auth-required", "default-config"]
published_at: "2026-11-13T10:17:45+00:00"
first_seen_at: "2026-11-13T10:47:19+00:00"
updated_at: "2026-11-13T10:53:13+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126405", "first_seen_at": "2026-11-13T10:47:19+00:00"}]
exploit_sources: []
---

# Coder: unbounded Web Push response read lets any user crash the server

Link for people: https://infrastack.ai/live/CVE-2026-126405 (this .md is for agents)

Coder reads Web Push endpoint responses with no size limit or timeout, so a registered subscription pointing at a server that returns an endless body exhausts memory. The result is that the API, dashboard and workspace connections crash.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the running Coder version with `coder version` and compare it to the ranges below.
- Review whether users can create Web Push subscriptions via POST /api/v2/users/{user}/webpush/subscription.

## Fix

- Coder `2.29.24` for the 2.21.x to 2.29.x line
- Coder `2.34.16` for the 2.30.x to 2.34.x line
- Coder `2.36.11` for the 2.35.x to 2.36.x line
- Coder `2.37.8` for the 2.37.x line
- Coder `2.38.4` for the 2.38.x line

## Timeline

- 2026-11-13T10:47:19+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-126405

## Documents

- [advisory] Vendor advisory: github.com https://github.com/coder/coder/security/advisories/GHSA-64xh-rgcx-gg65
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/coder-from-2.38.0-before-2.38.4-memory-exhaustion-dos-via-web-push

## From the sources

Coder 2.21.0 before 2.29.24, 2.30.0 before 2.34.16, 2.35.0 before 2.36.11, 2.37.0 before 2.37.8, and 2.38.0 before 2.38.4 reads Web Push endpoint responses in webpushSend with io.ReadAll, without a size limit or client timeout. Any authenticated user can register a subscription via POST /api/v2/users/{user}/webpush/subscription pointing to a server returning an endless body, exhausting coderd memory and crashing the API, dashboard, and workspace connections.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_