diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 2d188c5..d5115b1 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -59,7 +59,9 @@ jobs:
       # package (#44); `--msi` / `--instLocation PerMachine` are solidly
       # supported on the 1.2.0 line (bundled WiX 5). Mirrors ws-scrcpy-web's pin.
       - name: Install vpk CLI
-        run: dotnet tool install -g vpk --version 1.2.0
+        # Source-pinned to nuget.org + signature-validated via the repo nuget.config
+        # (audit #15: nuget.org-only source + signatureValidationMode=require).
+        run: dotnet tool install -g vpk --version 1.2.0 --configfile nuget.config
 
       # Restore + build per project directly (not via ControlMenu.sln) to
       # mirror the local-pack.ps1 approach (3x dotnet publish below).
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 004b83a..92868c2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -52,6 +52,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Traced SVGs are no longer served as navigable same-origin content.** The Tracing tool wrote its generated SVG under `wwwroot/temp` and pointed both the preview `<img>` and the Download Copy link at that `/temp/<id>.svg` URL. An SVG fetched from a same-origin URL is active content — an embedded `<script>` executes in the app's origin — so that URL was a stored-XSS primitive (reachable if the user opened or navigated to it). The preview and download now use an inert `data:image/svg+xml` URL (script-safe inside `<img>`, and forced to download rather than inline-rendered via the link's `download` attribute), and no SVG is written under `wwwroot/temp`. The SVG-Rasterize tool was reviewed too and is unaffected — it only writes its rasterized PNG/ICO output there, which is inert.
 - **The Jellyfin docker-compose parser bounds its input and validates the config path.** It read the compose file with no size limit and accepted whatever host path was mounted at `/config` — a path that then flows into `Path.Combine` and the sqlite3 cast/crew update. It now rejects a compose file larger than 1 MB before reading it, and rejects a `/config` host path that isn't a plain fully-qualified path (no quotes or control characters). A relative or Unix-style path that couldn't resolve to a local `jellyfin.db` on this host now returns a clear error instead of a silently-wrong path.
 - **Camera/ONVIF XML responses are parsed with a hardened reader (closes an entity-expansion DoS).** The ONVIF SOAP, WS-Discovery, and Hikvision ISAPI responses were parsed with `XDocument.Parse`. Contrary to the common "DTDs are prohibited by default" guidance — which applies to `XmlReader.Create`, **not** to `XDocument.Parse`/`Load(string)` — `Parse` allows DTDs and expands internal entities on .NET 10 (verified). A malicious device answering discovery could feed a billion-laughs-style payload (bounded by the framework's default entity cap, but still a real amplification); external entities were not fetched by default, so file-exfil XXE was not reachable. All three responses now route through one shared `SafeXml.Parse` that sets `DtdProcessing.Prohibit` (no DTD, no entity expansion), a null `XmlResolver`, and a ~1 MB document cap — closing the DoS and hardening against any future XXE regression.
+- **NuGet restores and the `vpk` install are source- and signature-pinned.** A repo `nuget.config` clears package sources to nuget.org only — so a stray machine/user feed or a typosquatting source can't substitute a malicious `vpk` (or any other package) — and sets `signatureValidationMode=require` with the nuget.org repository signer trusted, so every restored package must carry a valid nuget.org signature. The `vpk` install in `release.yml` and `local-pack.ps1` passes `--configfile` so the global-tool install is pinned the same way.
+- **The build's `.7z` extractor is vendored instead of taken from `PATH`.** `_Fetcher.ps1` extracted ImageMagick's portable `.7z` by shelling out to whatever `7z` happened to be on the runner's `PATH`; it now fetches a SHA-256-pinned `7zr.exe` into the build cache and extracts with that (Local-Dependencies-Only — build tools are vendored/fetched, never assumed present on the runner). 7-Zip publishes no signature or checksum for the standalone extractor, so the pinned hash is recorded from the official download and fails closed on any change.
+- **The in-app updater pins its release channel.** `VelopackUpdateService` now requests the `stable` channel explicitly — the channel `release.yml` publishes non-prerelease tags to — instead of relying on Velopack's RID-derived default, so the updater reliably matches the published stable releases and can't drift onto another channel. (Pinning the update package's publisher/signature is separate, future work — the Velopack Phase-2 signing initiative.)
 
 ## [1.2.0] - 2026-06-11
 
diff --git a/nuget.config b/nuget.config
new file mode 100644
index 0000000..ea79f33
--- /dev/null
+++ b/nuget.config
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Supply-chain pin for NuGet restores + `dotnet tool install vpk` (audit #15).
+
+  - packageSources is cleared to nuget.org ONLY, so a stray machine/user feed (or a
+    typosquatting source) can't substitute a malicious `vpk` (or any other package).
+  - signatureValidationMode=require rejects any package that is not signed by a trusted
+    signer. nuget.org repository-signs every package it serves, so the <trustedSigners>
+    entry below (the nuget.org repository signer, populated authoritatively via
+    `dotnet nuget trust source`) covers vpk and every other restored package.
+
+  This applies repo-wide (every `dotnet restore` / tool install run from the repo).
+-->
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
+  </packageSources>
+  <config>
+    <add key="signatureValidationMode" value="require" />
+  </config>
+  <trustedSigners>
+    <repository name="nuget.org" serviceIndex="https://api.nuget.org/v3/index.json">
+        <certificate fingerprint="0e5f38f57dc1bcc806d8494f4f90fbcedd988b46760709cbeec6f4219aa6157d" hashAlgorithm="SHA256" allowUntrustedRoot="false" />
+        <certificate fingerprint="5a2901d6ada3d18260b9c6dfe2133c95d74b9eef6ae0e5dc334c8454d1477df4" hashAlgorithm="SHA256" allowUntrustedRoot="false" />
+        <certificate fingerprint="1f4b311d9acc115c8dc8018b5a49e00fce6da8e2855f9f014ca6f34570bc482d" hashAlgorithm="SHA256" allowUntrustedRoot="false" />
+      </repository>
+  </trustedSigners>
+</configuration>
diff --git a/scripts/dependencies/_Fetcher.ps1 b/scripts/dependencies/_Fetcher.ps1
index 653d02a..a4fdfb8 100644
--- a/scripts/dependencies/_Fetcher.ps1
+++ b/scripts/dependencies/_Fetcher.ps1
@@ -82,28 +82,38 @@ function Expand-CmZip {
     Expand-Archive -LiteralPath $Archive -DestinationPath $DestDir -Force
 }
 
+function Get-Cm7zr {
+    # Resolves a vendored, SHA-pinned 7zr.exe -- the official 7-Zip standalone .7z extractor --
+    # fetched into the build cache rather than resolved from PATH. Local-Dependencies-Only: build
+    # tools are vendored/fetched into the app's own folder, never assumed present on the runner.
+    #
+    # Provenance note: 7-zip.org serves only the *latest* standalone extractor at this URL and
+    # publishes neither an Authenticode signature nor a checksum for it, so the SHA-256 below is
+    # recorded from the official download (trust-on-first-use). It still pins integrity: a tampered
+    # download fails the hash check, and a future 7-Zip release that changes 7zr.exe trips the same
+    # check fail-closed -- re-download, confirm provenance, and re-pin the SHA then.
+    $url    = 'https://www.7-zip.org/a/7zr.exe'
+    $sha256 = 'abcf64ae1cbafddb5395e4cdd3bdc7e3e0561d54a0c6380e3dd43bdbffe519a2'
+    $cache  = Get-CmCacheDir -Name '7zr' -Version 'latest'
+    $exe    = Join-Path $cache '7zr.exe'
+    Invoke-CmDownload -Url $url -DestFile $exe -ExpectedSha256 $sha256
+    return $exe
+}
+
 function Expand-Cm7z {
     param(
         [Parameter(Mandatory)][string] $Archive,
         [Parameter(Mandatory)][string] $DestDir
     )
-    # Some deps (ImageMagick) ship .7z portables. Expand-Archive can't read .7z,
-    # so shell out to 7-Zip. CI (windows-latest) has 7z on PATH; locally we fall
-    # back to the default install dir. 7z is a BUILD tool (like vpk / dotnet),
-    # not a bundled app dependency, so a system 7z is acceptable for staging.
-    $sevenZip = (Get-Command 7z -ErrorAction SilentlyContinue).Source
-    if (-not $sevenZip) {
-        $candidate = Join-Path $env:ProgramFiles '7-Zip\7z.exe'
-        if (Test-Path $candidate) { $sevenZip = $candidate }
-    }
-    if (-not $sevenZip) {
-        throw "7-Zip not found. CI runners have 7z on PATH; install 7-Zip locally to extract .7z deps."
-    }
+    # Some deps (ImageMagick) ship .7z portables that Expand-Archive can't read. Extract them with
+    # the vendored, SHA-pinned 7zr.exe fetched into the build cache (Get-Cm7zr) -- never a
+    # PATH-resolved 7z (Local-Dependencies-Only: a system 7z is no longer assumed present).
+    $sevenZip = Get-Cm7zr
     if (Test-Path $DestDir) { Remove-Item -LiteralPath $DestDir -Recurse -Force }
     New-Item -ItemType Directory -Path $DestDir -Force | Out-Null
-    Write-Host "  extracting : $Archive -> $DestDir (7z)"
+    Write-Host "  extracting : $Archive -> $DestDir (7zr)"
     & $sevenZip x $Archive "-o$DestDir" -y -bso0 -bsp0
-    if ($LASTEXITCODE -ne 0) { throw "7z extraction failed (exit $LASTEXITCODE): $Archive" }
+    if ($LASTEXITCODE -ne 0) { throw "7zr extraction failed (exit $LASTEXITCODE): $Archive" }
 }
 
 function Copy-CmStage {
diff --git a/scripts/local-pack.ps1 b/scripts/local-pack.ps1
index 5a633d8..c1126d0 100644
--- a/scripts/local-pack.ps1
+++ b/scripts/local-pack.ps1
@@ -19,7 +19,8 @@
 #   in the csprojs.
 #
 # Output: Releases/ControlMenu-<version>-Setup.msi + delta/full nupkgs +
-#   RELEASES.win.json feed. The MSI installs PerMachine to
+#   releases.stable.json feed (Velopack per-channel naming; this script packs
+#   --channel stable). The MSI installs PerMachine to
 #   C:\Program Files\ControlMenu\ with a UAC elevation prompt.
 
 param(
@@ -75,7 +76,9 @@ function Resolve-Vpk {
         Write-Host "Installing vpk $vpkVersion globally (matches the Velopack NuGet pin)..."
         # Uninstall any older vpk first to avoid version conflict
         dotnet tool uninstall -g vpk 2>$null | Out-Null
-        dotnet tool install -g vpk --version $vpkVersion
+        # Source-pinned to nuget.org + signature-validated via the repo nuget.config
+        # (audit #15: nuget.org-only source + signatureValidationMode=require).
+        dotnet tool install -g vpk --version $vpkVersion --configfile (Join-Path $PSScriptRoot '..\nuget.config')
         if ($LASTEXITCODE -ne 0) { throw "vpk install failed (exit $LASTEXITCODE)" }
         Write-Host "vpk $vpkVersion installed."
     }
diff --git a/src/ControlMenu/Services/Update/VelopackUpdateService.cs b/src/ControlMenu/Services/Update/VelopackUpdateService.cs
index 7803c7e..74de277 100644
--- a/src/ControlMenu/Services/Update/VelopackUpdateService.cs
+++ b/src/ControlMenu/Services/Update/VelopackUpdateService.cs
@@ -43,7 +43,14 @@ public VelopackUpdateService(IHostApplicationLifetime lifetime, ILogger<Velopack
     {
         _lifetime = lifetime;
         _log = log;
-        _manager = new UpdateManager(new GithubSource(GitHubRepo, accessToken: null, prerelease: false));
+        // Pin the update channel to "stable" — the channel release.yml packs non-prerelease tags
+        // into (`vpk pack --channel stable`; -beta/-alpha tags go to the "beta" channel). Without an
+        // explicit channel the updater falls back to Velopack's RID-derived default, which would not
+        // reliably match the published "stable" channel. (Publisher/signature pinning beyond the
+        // channel is deferred to the Velopack Phase-2 signing initiative.)
+        _manager = new UpdateManager(
+            new GithubSource(GitHubRepo, accessToken: null, prerelease: false),
+            new UpdateOptions { ExplicitChannel = "stable" });
     }
 
     public async Task<UpdateAvailability> CheckForUpdatesAsync(CancellationToken ct = default)