CVE-2025-59288: Microsoft Playwright Auth Bypass Vulnerability

CVE-2025-59288 Overview

CVE-2025-59288 affects Microsoft Playwright, an open-source browser automation framework maintained on GitHub. The vulnerability stems from improper verification of a cryptographic signature ([CWE-347]). An unauthorized attacker positioned on an adjacent network can exploit this weakness to perform spoofing against Playwright components. Because signature validation does not reliably reject malformed or forged signatures, attackers can present untrusted content as if it originated from a trusted source. Microsoft published the advisory on October 14, 2025.

Critical Impact
Adjacent-network attackers can spoof signed artifacts consumed by Microsoft Playwright, undermining the integrity guarantees the framework relies on for trusted execution.

Affected Products

Microsoft Playwright (GitHub distribution)
Playwright Node.js library and language bindings
Downstream test runners and automation pipelines using Playwright

Discovery Timeline

2025-10-14 - CVE-2025-59288 published to NVD
2025-10-14 - Microsoft Security Response Center advisory released
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-59288

Vulnerability Analysis

The flaw sits in the code path responsible for validating cryptographic signatures within Microsoft Playwright. Playwright relies on signature checks to confirm the authenticity of components it downloads, launches, or communicates with during automated browser sessions. When the verification routine fails to enforce signature correctness, an attacker can substitute attacker-controlled content while preserving the appearance of a valid signature.

Exploitation requires adjacent-network access, meaning the attacker must share a logical network segment such as the same Wi-Fi subnet, VLAN, or Bluetooth-adjacent link. The attack complexity is high because timing, path interception, and signature manipulation must align. No authentication or user interaction is required. Successful exploitation results in a spoofing outcome that impacts confidentiality of the trust decision.

Root Cause

The root cause is improper verification of a cryptographic signature classified under [CWE-347]. The verification logic accepts signatures without fully validating the signer, algorithm, or signed payload binding. This design gap allows forged or replayed signatures to satisfy the check.

Attack Vector

An attacker on an adjacent network intercepts or injects signed content that Playwright processes during setup or runtime operations. Because Playwright treats the malformed signature as valid, the attacker-controlled payload is trusted. Refer to the Microsoft Security Update for CVE-2025-59288 for authoritative technical details. No public proof-of-concept is currently available, and the CVE is not listed in the CISA Known Exploited Vulnerabilities catalog.

// No verified proof-of-concept code is publicly available for CVE-2025-59288.
// See the Microsoft Security Response Center advisory for technical guidance.

Detection Methods for CVE-2025-59288

Indicators of Compromise

Unexpected Playwright downloads or updates originating from hosts other than the official Microsoft or npm distribution endpoints.
Playwright browser binaries or driver executables whose hashes do not match the versions published by Microsoft.
TLS certificate anomalies or ARP spoofing activity on network segments hosting CI/CD runners that execute Playwright.

Detection Strategies

Monitor package manager and CI logs for Playwright installations that fetch dependencies from non-standard registries or mirrors.
Compare on-disk Playwright artifact hashes against the vendor-published values after every install or upgrade.
Alert on Playwright processes launching unsigned or unexpected child binaries during automated test runs.

Monitoring Recommendations

Enable network telemetry on subnets that host build agents, developer laptops, and QA infrastructure running Playwright.
Ingest CI/CD, endpoint, and network logs into a centralized analytics platform to correlate installation events with adjacent-network anomalies.
Track outbound connections initiated by Playwright to confirm they terminate at expected Microsoft or npm endpoints.

How to Mitigate CVE-2025-59288

Immediate Actions Required

Upgrade Microsoft Playwright to the fixed version identified in the Microsoft Security Response Center advisory.
Audit CI/CD pipelines and developer workstations to inventory every Playwright installation and pin versions to patched releases.
Restrict network access for build agents so they cannot be reached from untrusted adjacent segments.

Patch Information

Microsoft published the fix and remediation guidance in the MSRC update guide entry for CVE-2025-59288. Apply the vendor-supplied patched release of Playwright across all environments, then revalidate signed artifacts and dependencies after upgrade.

Workarounds

Isolate Playwright test runners on dedicated VLANs with strict ingress and egress rules to reduce adjacent-network exposure.
Enforce integrity verification by comparing downloaded Playwright binaries against known-good hashes before execution.
Require mutual TLS and pinned certificates for internal proxies that mediate Playwright artifact downloads.

bash

# Pin Playwright to a patched version and verify integrity
npm install --save-exact playwright@<patched-version>
npm audit signatures
sha256sum node_modules/playwright/package.json