Zip Bomb in Lookyloo Capture Upload Allows Denial of Service
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Active
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-400.
Summary
Lookyloo did not enforce limits on the decompressed size of uploaded capture archives and compressed HAR files. An attacker could submit a specially crafted ZIP, gzip, or zlib-compressed capture containing data that expands to a very large size during processing. Because the application decompressed this content directly in memory without first limiting the output size, processing the malicious capture could exhaust available memory, terminate a web or worker process, or make the Lookyloo instance unavailable. The vulnerability affects both full Lookyloo capture archive imports and API submissions containing gzip-compressed HAR data. Repeated exploitation could cause a persistent denial-of-service condition until the affected processes or instance are restarted. The patch introduces: * A 1 GB cumulative uncompressed-size limit for imported capture archives. * Size-limited gzip and zlib decompression for compressed HAR files. * Explicit detection and handling of suspected zip bombs. * An HTTP 400 response when an oversized compressed HAR file is submitted through the API.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-66913
References
More Lookyloo vulnerabilities
- TI-2025-40248 Lookyloo is vulnerable due to improper user input sanitization CVSS 4.0CRITICAL 9.4
- TI-2026-47455 Stored Cross-Site Scripting via Unsafe Capture Tree JSON Embedding CVSS 4.0CRITICAL 9.2
- TI-2026-79541 Lookyloo: Potential sub-system DoS due to parameter missmatch in notification CVSS 4.0MEDIUM 6.9
- TI-2026-58562 Server-Side Request Forgery via Favicon Redirect to Local Network Resources in PlaywrightCapture CVSS 4.0MEDIUM 6.9
- TI-2026-32379 LookyLoo - PlaywrightCapture permits access to local files and internal network resources during page capture CVSS 4.0MEDIUM 6.6
- TI-2026-45082 Cross-Capture Session Data Leakage Due to Shared Mutable State in Looklyloo - PlaywrightCapture CVSS 4.0HIGH 7.1
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences