diff --git a/packages/desktop/apps/electron/src/main/__tests__/network-proxy.test.ts b/packages/desktop/apps/electron/src/main/__tests__/network-proxy.test.ts
index 159f77f9085..80696305723 100644
--- a/packages/desktop/apps/electron/src/main/__tests__/network-proxy.test.ts
+++ b/packages/desktop/apps/electron/src/main/__tests__/network-proxy.test.ts
@@ -30,7 +30,18 @@ describe('parseNoProxyRules', () => {
 
   it('parses host:port', () => {
     const rules = parseNoProxyRules('example.com:8080');
-    expect(rules).toEqual([{ host: 'example.com', port: 8080, wildcard: false }]);
+    expect(rules).toEqual([
+      { host: 'example.com', port: 8080, wildcard: false },
+    ]);
+  });
+
+  it('does not parse malformed port suffixes', () => {
+    expect(parseNoProxyRules('example.com:443abc')).toEqual([
+      { host: 'example.com:443abc', wildcard: false },
+    ]);
+    expect(parseNoProxyRules('[::1]:abc')).toEqual([
+      { host: '[::1]:abc', wildcard: false },
+    ]);
   });
 });
 
@@ -55,7 +66,9 @@ describe('shouldBypassProxy', () => {
   it('respects port-scoped rules', () => {
     const rules = parseNoProxyRules('example.com:8080');
     expect(shouldBypassProxy('http://example.com:8080/path', rules)).toBe(true);
-    expect(shouldBypassProxy('http://example.com:9090/path', rules)).toBe(false);
+    expect(shouldBypassProxy('http://example.com:9090/path', rules)).toBe(
+      false,
+    );
   });
 
   it('matches implicit default ports', () => {
@@ -71,7 +84,9 @@ describe('shouldBypassProxy', () => {
 
     // Explicit port that differs from rule should not match
     const rules8080 = parseNoProxyRules('example.com:8080');
-    expect(shouldBypassProxy('https://example.com/path', rules8080)).toBe(false);
+    expect(shouldBypassProxy('https://example.com/path', rules8080)).toBe(
+      false,
+    );
   });
 
   it('wildcard bypasses everything', () => {
@@ -84,6 +99,27 @@ describe('shouldBypassProxy', () => {
     expect(shouldBypassProxy('http://[::1]:3000/path', rules)).toBe(true);
   });
 
+  it('respects IPv6 port-scoped rules', () => {
+    const rules = parseNoProxyRules('[::1]:3000');
+    expect(shouldBypassProxy('http://[::1]:3000/path', rules)).toBe(true);
+    expect(shouldBypassProxy('http://[::1]:3001/path', rules)).toBe(false);
+  });
+
+  it('does not bypass for malformed port suffixes', () => {
+    expect(
+      shouldBypassProxy(
+        'https://example.com/path',
+        parseNoProxyRules('example.com:443abc'),
+      ),
+    ).toBe(false);
+    expect(
+      shouldBypassProxy(
+        'http://[::1]:3000/path',
+        parseNoProxyRules('[::1]:abc'),
+      ),
+    ).toBe(false);
+  });
+
   it('matches exact IP literal', () => {
     const rules = parseNoProxyRules('192.168.1.1');
     expect(shouldBypassProxy('http://192.168.1.1/', rules)).toBe(true);
diff --git a/packages/desktop/apps/electron/src/main/network-proxy-utils.ts b/packages/desktop/apps/electron/src/main/network-proxy-utils.ts
index 50194c37517..974c4fa6de6 100644
--- a/packages/desktop/apps/electron/src/main/network-proxy-utils.ts
+++ b/packages/desktop/apps/electron/src/main/network-proxy-utils.ts
@@ -7,7 +7,10 @@
 /** Split a comma-separated string into trimmed, non-empty entries. */
 export function splitCommaSeparated(str: string | undefined): string[] {
   if (!str) return [];
-  return str.split(',').map(s => s.trim()).filter(Boolean);
+  return str
+    .split(',')
+    .map((s) => s.trim())
+    .filter(Boolean);
 }
 
 export interface NoProxyRule {
@@ -19,6 +22,14 @@ export interface NoProxyRule {
   wildcard: boolean;
 }
 
+function parsePort(raw: string): number | undefined {
+  if (!/^\d+$/.test(raw)) return undefined;
+  const port = Number(raw);
+  return Number.isInteger(port) && port >= 0 && port <= 65535
+    ? port
+    : undefined;
+}
+
 /**
  * Parse a comma-separated NO_PROXY string into structured rules.
  *
@@ -33,8 +44,8 @@ export function parseNoProxyRules(noProxy: string | undefined): NoProxyRule[] {
   if (!noProxy) return [];
 
   return splitCommaSeparated(noProxy)
-    .map(entry => entry.toLowerCase())
-    .map(entry => {
+    .map((entry) => entry.toLowerCase())
+    .map((entry) => {
       if (entry === '*') {
         return { host: '*', wildcard: true };
       }
@@ -49,12 +60,15 @@ export function parseNoProxyRules(noProxy: string | undefined): NoProxyRule[] {
           const ipv6Host = cleaned.slice(1, closeBracket);
           const afterBracket = cleaned.slice(closeBracket + 1);
           if (afterBracket.startsWith(':')) {
-            const port = parseInt(afterBracket.slice(1), 10);
-            if (!isNaN(port)) {
+            const port = parsePort(afterBracket.slice(1));
+            if (port !== undefined) {
               return { host: ipv6Host, port, wildcard: false };
             }
           }
-          return { host: ipv6Host, wildcard: false };
+          if (afterBracket === '') {
+            return { host: ipv6Host, wildcard: false };
+          }
+          return { host: cleaned, wildcard: false };
         }
       }
 
@@ -62,8 +76,8 @@ export function parseNoProxyRules(noProxy: string | undefined): NoProxyRule[] {
       const lastColon = cleaned.lastIndexOf(':');
       if (lastColon > 0) {
         const host = cleaned.slice(0, lastColon);
-        const port = parseInt(cleaned.slice(lastColon + 1), 10);
-        if (!isNaN(port)) {
+        const port = parsePort(cleaned.slice(lastColon + 1));
+        if (port !== undefined) {
           return { host, port, wildcard: false };
         }
       }
@@ -78,14 +92,19 @@ export function parseNoProxyRules(noProxy: string | undefined): NoProxyRule[] {
 /** Default ports by protocol, used when URL omits an explicit port. */
 const DEFAULT_PORTS: Record<string, number> = { 'http:': 80, 'https:': 443 };
 
-export function shouldBypassProxy(url: string | URL, rules: NoProxyRule[]): boolean {
+export function shouldBypassProxy(
+  url: string | URL,
+  rules: NoProxyRule[],
+): boolean {
   if (rules.length === 0) return false;
 
   const parsed = typeof url === 'string' ? new URL(url) : url;
   const hostname = parsed.hostname.toLowerCase();
   // Strip brackets from IPv6
   const host = hostname.startsWith('[') ? hostname.slice(1, -1) : hostname;
-  const port = parsed.port ? parseInt(parsed.port, 10) : DEFAULT_PORTS[parsed.protocol];
+  const port = parsed.port
+    ? parseInt(parsed.port, 10)
+    : DEFAULT_PORTS[parsed.protocol];
 
   for (const rule of rules) {
     if (rule.wildcard) return true;