NVD / CVE Program· CNA CIRCL

CVE-2026-66913: Zip Bomb in Lookyloo Capture Upload Allows Denial of Service

Noroxi assessment

Priority: Monitor (action score 27/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.42% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
No fixed version is recorded, but the references include a patch (commit or PR) link.

Low priority for now. See the fix and affected versions sections below.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.9 · v4.0—No exploit No fix recorded

Published: Jul 28, 2026
Updated: Jul 30, 2026
EPSS: 0.4% · 37th percentile
CWE: CWE-400

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 27 / 40 · 6.9 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · CIRCL: 6.9; NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (CIRCL). Independent of NVD's CPE analysis and usually ahead of it.

lookyloo lookyloo
- up to and including 1.40.0affected · semver

Same product

lookyloo: all records

Other highest-scoring records for the same primary product.

CVE-2025-65095Lookyloo is vulnerable due to improper user input sanitization
37Monitor
CVE-2026-66824Stored Cross-Site Scripting via Unsafe Capture Tree JSON Embedding
36Monitor
CVE-2026-55835Lookyloo: Potential sub-system DoS due to parameter missmatch in notification
27Monitor

Published before and after this one in the same product

← EarlierCVE-2025-66458Dec 2, 2025 · Lookyloo has multiple XSS due to unsafe use of f-strings in Markup
21Monitor
← EarlierCVE-2025-66459Dec 2, 2025 · Lookyloo vulnerable to XSS due to unescaped error message passed to innerHTML
21Monitor
← EarlierCVE-2025-66460Dec 2, 2025 · Lookyloo vulnerable to XSS due to lack of escaping in HTML elements passed to Datatables
21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Lookyloo/lookyloocommit 96589da

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Raphael Vinotremediation developer
https://github.com/EQSTLabfinder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: A
Scope: X

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

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

nvd-secondary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

github.com/Lookyloo/lookyloo/commit/96589da290f018e356db7c0eaddf1aa501630ca7

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records