Claude HUD's AI-written code accepted an unvalidated transcript_path from stdin JSON, enabling arbitrary file reads and leaving permissive cached metadata.

-  COMPACTION_THRESHOLD,-  WARNING_THRESHOLD,-  CHARS_PER_TOKEN,-  DEFAULT_MAX_TOKENS,-  TOKEN_HISTORY_SIZE,-  BURN_RATE_SAMPLE_SIZE,-} from './constants.js';--const SPARKLINE_SAMPLES = 20;--interface TokenSample {-  tokens: number;-  timestamp: number;-}--interface TranscriptUsage {-  input_tokens?: number;-  output_tokens?: number;-  cache_creation_input_tokens?: number;-  cache_read_input_tokens?: number;-}--interface TranscriptMessage {-  message?: {-    model?: string;-    usage?: TranscriptUsage;-  };-  type?: string;-}--const MODEL_CONTEXT_LIMITS: Record<string, number> = {-  'claude-opus-4-5': DEFAULT_MAX_TOKENS,-  'claude-sonnet-4': DEFAULT_MAX_TOKENS,-  'claude-haiku-3-5': DEFAULT_MAX_TOKENS,-  default: DEFAULT_MAX_TOKENS,-};--function getContextLimit(model: string | null): number {-  if (!model) return MODEL_CONTEXT_LIMITS['default'];-  for (const [key, limit] of Object.entries(MODEL_CONTEXT_LIMITS)) {-    if (model.includes(key)) return limit;-  }-  return MODEL_CONTEXT_LIMITS['default'];-}--export class UnifiedContextTracker {-  private transcriptPath: string | null = null;-  private transcriptModified: number = 0;-  private model: string | null = null;-  private realTokens: number = 0;-  private estimatedDelta: number = 0;-  private breakdown: ContextBreakdown = {-    toolOutputs: 0,-    toolInputs: 0,-    messages: 0,-    other: 0,-  };-  private tokenHistory: TokenSample[] = [];-  private sessionStart: number;-  private lastUpdate: number;-  private compactionCount: number = 0;-  private transcriptOffset = 0;-  private transcriptRemainder = '';-  private transcriptUsage: TranscriptUsage | null = null;--  constructor() {-    this.sessionStart = Date.now();-    this.lastUpdate = this.sessionStart;-  }--  setTranscriptPath(path: string): void {-    if (this.transcriptPath !== path) {-      this.transcriptPath = path;-      this.resetTranscriptState();-      this.readTranscript();-    }-  }--  private estimateTokens(text: string): number {-    if (!text) return 0;-    return Math.ceil(text.length / CHARS_PER_TOKEN);-  }--  processEvent(event: HudEvent): void {-    this.lastUpdate = Date.now();

-import { UnifiedContextTracker } from './unified-context-tracker.js';-import type { HudEvent } from './types.js';--function createEvent(overrides: Partial<HudEvent> = {}): HudEvent {-  return {-    event: 'PostToolUse',-    tool: 'Read',-    toolUseId: `tool-${Date.now()}`,-    input: { file_path: '/test/file.ts' },-    response: { content: 'file content here' },-    session: 'test-session',-    ts: Math.floor(Date.now() / 1000),-    ...overrides,-  };-}--describe('UnifiedContextTracker', () => {-  let tracker: UnifiedContextTracker;--  beforeEach(() => {-    tracker = new UnifiedContextTracker();-  });--  describe('getHealth', () => {-    it('returns initial health with zero tokens', () => {-      const health = tracker.getHealth();--      expect(health.tokens).toBe(0);-      expect(health.percent).toBe(0);-      expect(health.remaining).toBe(200000);-      expect(health.maxTokens).toBe(200000);-      expect(health.status).toBe('healthy');-      expect(health.shouldCompact).toBe(false);-    });-  });--  describe('processEvent', () => {-    it('estimates tokens from PostToolUse events', () => {-      const event = createEvent({-        input: { content: 'a'.repeat(400) },-        response: { result: 'b'.repeat(400) },-      });--      tracker.processEvent(event);-      const health = tracker.getHealth();--      expect(health.tokens).toBeGreaterThan(0);-      expect(health.breakdown.toolInputs).toBeGreaterThan(0);-      expect(health.breakdown.toolOutputs).toBeGreaterThan(0);-    });--    it('tracks compaction count from PreCompact events', () => {-      expect(tracker.getCompactionCount()).toBe(0);--      tracker.processEvent(createEvent({ event: 'PreCompact' }));-      expect(tracker.getCompactionCount()).toBe(1);--      tracker.processEvent(createEvent({ event: 'PreCompact' }));-      expect(tracker.getCompactionCount()).toBe(2);-    });--    it('reads new content even when mtime unchanged but file grew', () => {-      const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'claude-hud-mtime-'));-      const transcriptPath = path.join(tmpDir, 'transcript.jsonl');--      const first = {-        type: 'assistant',-        message: { model: 'claude-sonnet-4', usage: { input_tokens: 100, output_tokens: 50 } },-      };-      fs.writeFileSync(transcriptPath, `${JSON.stringify(first)}\n`, 'utf-8');--      tracker.setTranscriptPath(transcriptPath);-      tracker.processEvent(createEvent({ event: 'Stop' }));--      const firstHealth = tracker.getHealth();-      expect(firstHealth.tokens).toBe(150);--      // Append new content without changing mtime (simulates rapid writes)-      const second = {-        type: 'assistant',-        message: { model: 'claude-sonnet-4', usage: { input_tokens: 300, output_tokens: 200 } },-      };-      fs.appendFileSync(transcriptPath, `${JSON.stringify(second)}\n`, 'utf-8');--      // Force mtime to stay the same (simulates filesystem granularity issue)

--function createState() {-  return createInitialHudState({-    context: {-      tokens: 0,-      percent: 0,-      remaining: 0,-      maxTokens: 0,-      burnRate: 0,-      status: 'healthy',-      shouldCompact: false,-      breakdown: { toolOutputs: 0, toolInputs: 0, messages: 0, other: 0 },-      sessionStart: 0,-      lastUpdate: 0,-      tokenHistory: [],-    },-    cost: { inputCost: 0, outputCost: 0, totalCost: 0, inputTokens: 0, outputTokens: 0 },-  });-}--describe('reduceHudState', () => {-  it('tracks tool lifecycle from PreToolUse to PostToolUse', () => {-    const state = createState();-    const preEvent: HudEvent = {-      schemaVersion: 1,-      event: 'PreToolUse',-      tool: 'Read',-      toolUseId: 'tool-1',-      input: { file_path: 'README.md' },-      response: null,-      session: 's1',-      ts: 100,-    };--    const afterPre = reduceHudState(state, { type: 'event', event: preEvent, now: 1000 });-    expect(afterPre.tools).toHaveLength(1);-    expect(afterPre.tools[0]?.status).toBe('running');-    expect(afterPre.sessionInfo.isIdle).toBe(false);-    expect(afterPre.runningTools.has('tool-1')).toBe(true);--    const postEvent: HudEvent = {-      schemaVersion: 1,-      event: 'PostToolUse',-      tool: 'Read',-      toolUseId: 'tool-1',-      input: null,-      response: { duration_ms: 250 },-      session: 's1',-      ts: 100,-    };--    const afterPost = reduceHudState(afterPre, { type: 'event', event: postEvent, now: 1300 });-    expect(afterPost.tools[0]?.status).toBe('complete');-    expect(afterPost.runningTools.has('tool-1')).toBe(false);-    expect(afterPost.tools[0]?.duration).toBe(250);-  });--  it('applies todo updates and agent lifecycle', () => {-    const state = createState();-    const todoEvent: HudEvent = {-      schemaVersion: 1,-      event: 'PreToolUse',-      tool: 'TodoWrite',-      toolUseId: 'todo-1',-      input: { todos: [{ content: 'Ship HUD tests', status: 'in_progress' }] },-      response: null,-      session: 's1',-      ts: 200,-    };-    const afterTodo = reduceHudState(state, { type: 'event', event: todoEvent, now: 2000 });-    expect(afterTodo.todos).toHaveLength(1);--    const taskEvent: HudEvent = {-      schemaVersion: 1,-      event: 'PreToolUse',-      tool: 'Task',-      toolUseId: 'agent-1',-      input: { subagent_type: 'Research', description: 'Check HUD output' },-      response: null,-      session: 's1',-      ts: 300,-    };-    const afterTask = reduceHudState(afterTodo, { type: 'event', event: taskEvent, now: 3000 });-    expect(afterTask.agents).toHaveLength(1);-    expect(afterTask.agents[0]?.status).toBe('running');

+    return null;+  }+}+ function readTranscriptFileState(transcriptPath: string): TranscriptFileState | null {   try {     const stat = fs.statSync(transcriptPath);@@ -181,7 +189,7 @@ function writeTranscriptCache(transcriptPath: string, state: TranscriptFileState       transcriptState: state,       data: serializeTranscriptData(data),     };-    fs.writeFileSync(cachePath, JSON.stringify(payload), 'utf8');+    fs.writeFileSync(cachePath, JSON.stringify(payload), { encoding: 'utf8', mode: 0o600 });   } catch {     // Cache failures are non-fatal; fall back to fresh parsing next time.   }@@ -198,12 +206,17 @@ export async function parseTranscript(transcriptPath: string): Promise<Transcrip     return result;   } -  const transcriptState = readTranscriptFileState(transcriptPath);+  const canonicalTranscriptPath = canonicalizeTranscriptPath(transcriptPath);+  if (!canonicalTranscriptPath) {+    return result;+  }++  const transcriptState = readTranscriptFileState(canonicalTranscriptPath);   if (!transcriptState) {     return result;   } -  const cached = readTranscriptCache(transcriptPath, transcriptState);+  const cached = readTranscriptCache(canonicalTranscriptPath, transcriptState);   if (cached) {     return cached;   }@@ -224,7 +237,7 @@ export async function parseTranscript(transcriptPath: string): Promise<Transcrip   let parsedCleanly = false;    try {-    const fileStream = createReadStreamImpl(transcriptPath);+    const fileStream = createReadStreamImpl(canonicalTranscriptPath);     const rl = readline.createInterface({       input: fileStream,       crlfDelay: Infinity,@@ -265,7 +278,7 @@ export async function parseTranscript(transcriptPath: string): Promise<Transcrip   result.sessionName = customTitle ?? latestSlug;   result.sessionTokens = sessionTokens;   if (parsedCleanly) {-    writeTranscriptCache(transcriptPath, transcriptState, result);+    writeTranscriptCache(canonicalTranscriptPath, transcriptState, result);   }    return result;

 import { git as gitColor, gitBranch as gitBranchColor, warning as warningColor, critical as criticalColor, label, model as modelColor, project as projectColor, red, green, yellow, dim, custom as customColor } from '../colors.js'; import { t } from '../../i18n/index.js'; import { renderCostEstimate } from './cost.js'; +const CONTROL_AND_BIDI_PATTERN = /[\^@-\^_\u007F-\^_\u061C\u200E\u200F\u202A-\u202E\u2066-\u2069\u206A-\u206F]/g;+ function hyperlink(uri: string, text: string): string {   const esc = '\x1b';   const st = '\\';   return `${esc}]8;;${uri}${esc}${st}${text}${esc}]8;;${esc}${st}`; } +function sanitizeDisplayText(value: string): string {+  return value.replace(CONTROL_AND_BIDI_PATTERN, '');+}++function getFileHref(filePath: string): string | null {+  try {+    return pathToFileURL(path.resolve(filePath)).toString();+  } catch {+    return null;+  }+}++function resolvePathWithinCwd(cwd: string, candidatePath: string): string | null {+  const resolvedCwd = path.resolve(cwd);+  const resolvedPath = path.resolve(cwd, candidatePath);+  const relative = path.relative(resolvedCwd, resolvedPath);+  if (relative === '' || (!relative.startsWith('..') && !path.isAbsolute(relative))) {+    return resolvedPath;+  }+  return null;+}++function safeHyperlink(uri: string | undefined | null, text: string): string {+  if (!uri) {+    return text;+  }++  const sanitizedUri = sanitizeDisplayText(uri);+  try {+    const parsed = new URL(sanitizedUri);+    if (parsed.protocol !== 'https:' && parsed.protocol !== 'file:') {+      return text;+    }+    return hyperlink(parsed.toString(), text);+  } catch {+    return text;+  }+}+ export function renderProjectLine(ctx: RenderContext): string | null {   const display = ctx.config?.display;   const colors = ctx.config?.colors;@@ -35,9 +77,9 @@ export function renderProjectLine(ctx: RenderContext): string | null {   if (display?.showProject !== false && ctx.stdin.cwd) {     const segments = ctx.stdin.cwd.split(/[/\\]/).filter(Boolean);     const pathLevels = ctx.config?.pathLevels ?? 1;-    const projectPath = segments.length > 0 ? segments.slice(-pathLevels).join('/') : '/';+    const projectPath = sanitizeDisplayText(segments.length > 0 ? segments.slice(-pathLevels).join('/') : '/');     const coloredProject = projectColor(projectPath, colors);-    projectPart = hyperlink(`file://${ctx.stdin.cwd}`, coloredProject);+    projectPart = safeHyperlink(getFileHref(ctx.stdin.cwd), coloredProject);   }    let gitPart = '';@@ -46,9 +88,11 @@ export function renderProjectLine(ctx: RenderContext): string | null {   const branchOverflow = gitConfig?.branchOverflow ?? 'truncate';    if (showGit && ctx.gitStatus) {-    const branchText = ctx.gitStatus.branch + ((gitConfig?.showDirty ?? true) && ctx.gitStatus.isDirty ? '*' : '');+    const branchText = sanitizeDisplayText(+      ctx.gitStatus.branch + ((gitConfig?.showDirty ?? true) && ctx.gitStatus.isDirty ? '*' : '')+    );     const coloredBranch = gitBranchColor(branchText, colors);-    const linkedBranch = ctx.gitStatus.branchUrl ? hyperlink(ctx.gitStatus.branchUrl, coloredBranch) : coloredBranch;+    const linkedBranch = safeHyperlink(ctx.gitStatus.branchUrl, coloredBranch);     const gitInner: string[] = [linkedBranch];      if (gitConfig?.showAheadBehind) {@@ -156,8 +200,10 @@ export function renderGitFilesLine(ctx: RenderContext, terminalWidth: number | n   const cwd = ctx.stdin.cwd;   const sorted = [...trackedFiles].sort((a, b) => {

 let hasResolved = false;@@ -199,13 +199,13 @@ export function _parseClaudeCodeVersion(output: string): string | undefined { export function _getClaudeVersionInvocation(   binaryPath: string,   platform: NodeJS.Platform = platformImpl(),-  comspec: string | undefined = comspecImpl()+  windowsCmd: string = windowsCmdImpl() ): ClaudeVersionInvocation {   const ext = path.extname(binaryPath).toLowerCase();   if (platform === 'win32' && (ext === '.cmd' || ext === '.bat')) {     const command = [quoteForCmd(binaryPath), '--version'].join(' ');     return {-      file: comspec || 'cmd.exe',+      file: windowsCmd,       args: ['/d', '/s', '/c', `"${command}"`],     };   }@@ -297,8 +297,8 @@ export function _setResolveClaudeBinaryForTests(impl: (() => ClaudeBinaryInfo |  export function _setVersionInvocationEnvForTests(   platformGetter: (() => NodeJS.Platform) | null,-  comspecGetter: (() => string | undefined) | null+  windowsCmdGetter: (() => string) | null ): void {   platformImpl = platformGetter ?? (() => process.platform);-  comspecImpl = comspecGetter ?? (() => process.env.COMSPEC);+  windowsCmdImpl = windowsCmdGetter ?? (() => 'C:\\Windows\\System32\\cmd.exe'); }