CVE-2026-66913
Zip Bomb in Lookyloo Capture Upload Allows Denial of Service
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Active
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
6.9
Zip Bomb in Lookyloo Capture Upload Allows Denial of Service
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.
- Record
CVE-2026-66913- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2026-49768
6.9
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.
- Record
EUVD-2026-49768- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
NVD
6.9
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.
- Record
CVE-2026-66913- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-400
- Updated
- 2026-11-02
OSV
6.9
Zip Bomb in Lookyloo Capture Upload Allows Denial of Service
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.
- Record
CVE-2026-66913- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-400
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-66913 is a medium vulnerability (CVSS 6.9) in Lookyloo, published July 28, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. No source names a fixed version.