CVE-2026-66913 Zip Bomb in Lookyloo Capture Upload Allows Denial of Service
Attackers can cause denial of service in Lookyloo by uploading zip bombs that exhaust memory during decompression.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-66913?
CVE-2026-66913 is a medium-severity denial of service vulnerability in lookyloo, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-400
Which versions are affected by CVE-2026-66913?
How do I fix CVE-2026-66913?
No fix has been published for CVE-2026-66913 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-66913 being exploited?
There is no known exploitation of CVE-2026-66913 in the wild and no public exploit code.