diff --git a/Dockerfile b/Dockerfile
index 5f3f4e3e7..6d43beefa 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 # Enables BuildKit with cache mounts for faster builds
-FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.26 AS builder
+FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.25 AS builder
 
 ARG TARGETOS TARGETARCH
 
diff --git a/docs/changelogs/v0.40.md b/docs/changelogs/v0.40.md
index 6e20d1c3d..175022350 100644
--- a/docs/changelogs/v0.40.md
+++ b/docs/changelogs/v0.40.md
@@ -5,6 +5,7 @@
 This release was brought to you by the [Shipyard](https://ipshipyard.com/) team.
 
 - [v0.40.0](#v0400)
+- [v0.40.1](#v0401)
 
 ## v0.40.0
 
@@ -341,6 +342,8 @@ This release is built with [Go 1.26](https://go.dev/doc/go1.26).
 
 You should see lower memory usage and reduced GC pauses thanks to the new Green Tea garbage collector (10-40% less GC overhead). Reading block data and API responses is faster due to `io.ReadAll` improvements (~2x faster, ~50% less memory). On 64-bit platforms, heap base address randomization adds a layer of security hardening.
 
+> **Note:** [v0.40.1](#v0401) downgrades to Go 1.25 due to a Windows stability issue. If you run Kubo on Linux or macOS, staying on v0.40.0 is fine and you benefit from Go 1.26's GC improvements.
+
 #### 📦️ Dependency updates
 
 - update `go-libp2p` to [v0.47.0](https://github.com/libp2p/go-libp2p/releases/tag/v0.47.0) (incl. [v0.46.0](https://github.com/libp2p/go-libp2p/releases/tag/v0.46.0))
@@ -620,3 +623,22 @@ You should see lower memory usage and reduced GC pauses thanks to the new Green
 | [@willscott](https://github.com/willscott) | 1 | +1/-1 | 1 |
 | [@lbarrettanderson](https://github.com/lbarrettanderson) | 1 | +1/-1 | 1 |
 | [@filipremb](https://github.com/filipremb) | 1 | +1/-1 | 1 |
+
+## v0.40.1
+
+### 🔦 Highlights
+
+#### Windows stability fix
+
+If you run Kubo on Windows, v0.40.0 can crash after running for a while. The daemon starts fine and works normally at first, but eventually hits a memory corruption in Go's network I/O layer and dies. This is likely caused by an upstream Go 1.26 regression in overlapped I/O handling that has known issues ([go#77142](https://github.com/golang/go/issues/77142), [#11214](https://github.com/ipfs/kubo/issues/11214)).
+
+This patch release downgrades the Go toolchain from 1.26 to 1.25, which does not have this bug. If you are running Kubo on Windows, upgrade to v0.40.1. We will switch back to Go 1.26.x once the upstream fix lands.
+
+### 📝 Changelog
+
+<details><summary>Full Changelog v0.40.1</summary>
+
+- github.com/ipfs/kubo:
+  - chore: downgrade to Go 1.25 to fix Windows crash ([ipfs/kubo#11215](https://github.com/ipfs/kubo/pull/11215))
+
+</details>
diff --git a/docs/examples/kubo-as-a-library/go.mod b/docs/examples/kubo-as-a-library/go.mod
index 0b56d2bc3..a0be7d155 100644
--- a/docs/examples/kubo-as-a-library/go.mod
+++ b/docs/examples/kubo-as-a-library/go.mod
@@ -1,6 +1,6 @@
 module github.com/ipfs/kubo/examples/kubo-as-a-library
 
-go 1.26
+go 1.25.0
 
 // Used to keep this in sync with the current version of kubo. You should remove
 // this if you copy this example.
diff --git a/go.mod b/go.mod
index cde4e7f54..cfffd2b69 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/ipfs/kubo
 
-go 1.26
+go 1.25.0
 
 require (
 	bazil.org/fuse v0.0.0-20200117225306-7b5117fecadc
diff --git a/test/dependencies/go.mod b/test/dependencies/go.mod
index 798c97df1..bb890a1c1 100644
--- a/test/dependencies/go.mod
+++ b/test/dependencies/go.mod
@@ -1,6 +1,6 @@
 module github.com/ipfs/kubo/test/dependencies
 
-go 1.26
+go 1.25.0
 
 replace github.com/ipfs/kubo => ../../