diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index a00ec301..9dbd0954 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -31,7 +31,7 @@ jobs:
         run: df -h
       - uses: golangci/golangci-lint-action@v9
         with:
-          version: v2.6.2
+          version: v2.11.4
 
   tests:
     runs-on: ubuntu-latest
diff --git a/AGENTS.md b/AGENTS.md
index 6c7a6e0d..70b5892a 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -4,7 +4,7 @@
 
 ### Essential Setup
 ```bash
-# Check Go version (requires 1.24.2+)
+# Check Go version (requires 1.26.2+)
 go version
 
 # Check Helm dependency (required at runtime)
diff --git a/Dockerfile b/Dockerfile
index a0d85f56..14814512 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM --platform=$BUILDPLATFORM golang:1.25-alpine AS builder
+FROM --platform=$BUILDPLATFORM golang:1.26-alpine AS builder
 
 RUN apk add --no-cache make git
 WORKDIR /workspace/helmfile
diff --git a/Dockerfile.debian-stable-slim b/Dockerfile.debian-stable-slim
index a0fe5b7a..5a2b703f 100644
--- a/Dockerfile.debian-stable-slim
+++ b/Dockerfile.debian-stable-slim
@@ -1,4 +1,4 @@
-FROM --platform=$BUILDPLATFORM golang:1.25-alpine AS builder
+FROM --platform=$BUILDPLATFORM golang:1.26-alpine AS builder
 
 RUN apk add --no-cache make git
 WORKDIR /workspace/helmfile
diff --git a/Dockerfile.ubuntu b/Dockerfile.ubuntu
index f8f9d40b..486736c9 100644
--- a/Dockerfile.ubuntu
+++ b/Dockerfile.ubuntu
@@ -1,4 +1,4 @@
-FROM --platform=$BUILDPLATFORM golang:1.25-alpine AS builder
+FROM --platform=$BUILDPLATFORM golang:1.26-alpine AS builder
 
 RUN apk add --no-cache make git
 WORKDIR /workspace/helmfile
diff --git a/go.mod b/go.mod
index 6d48d838..9fa2589f 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/helmfile/helmfile
 
-go 1.25.8
+go 1.26.2
 
 require (
 	dario.cat/mergo v1.0.2
diff --git a/pkg/helmexec/exec.go b/pkg/helmexec/exec.go
index 4b061266..5af9add0 100644
--- a/pkg/helmexec/exec.go
+++ b/pkg/helmexec/exec.go
@@ -256,7 +256,7 @@ func (helm *execer) AddRepo(name, repository, cafile, certfile, keyfile, usernam
 		if username != "" && password != "" {
 			args = append(args, "--username", username, "--password-stdin")
 			buffer := bytes.Buffer{}
-			buffer.Write([]byte(fmt.Sprintf("%s\n", password)))
+			fmt.Fprintf(&buffer, "%s\n", password)
 			out, err = helm.execStdIn(args, map[string]string{}, &buffer)
 		} else {
 			out, err = helm.exec(args, map[string]string{}, nil)
@@ -311,7 +311,7 @@ func (helm *execer) RegistryLogin(repository, username, password, caFile, certFi
 
 	args = append(args, "--username", username, "--password-stdin")
 	buffer := bytes.Buffer{}
-	buffer.Write([]byte(fmt.Sprintf("%s\n", password)))
+	fmt.Fprintf(&buffer, "%s\n", password)
 
 	helm.logger.Info("Logging in to registry")
 	out, err := helm.execStdIn(args, map[string]string{"HELM_EXPERIMENTAL_OCI": "1"}, &buffer)