CVE Intelligence
Medium

CVE-2026-55835 — Lookyloo: Potential sub-system DoS due to parameter missmatch in notification

Lookyloo is a web interface that allows users to capture a website page and then display a tree of domains that call each other. Prior to version 1.39.4, an unauthenticated user can trigger Lookyloo's "report a capture" email on demand (this is expected). The /json/<uuid>/report API endpoint (CaptureReport) is incorrectly passing the email and comment parameters, overwriting as_admin. When True, as_admin will trigger a search query on a MISP instance (if configured) and add a list of matching URLs in the email sent to the analyst (not the submitter, so there is no risk of leaking information) . It could potentially cause a DoS on the MISP instance. This issue has been patched in version 1.39.4.

Published Oct 23, 2026 · Updated Oct 23, 2026 · Sources: CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.4% (30-day exploitation probability)+5
  • Technical severity (medium)+3
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.39%
ahead of 34% of scored CVEs · Oct 30, 2026
Affects
Lookyloo
Lookyloo
CVSS base
6.9
Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Lookyloo Lookyloo).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Lookyloo Lookyloo version < 1.39.4 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
None
Scope
X
Confidentiality (vulnerable system)
None
Integrity (vulnerable system)
None
Availability (vulnerable system)
None
Confidentiality (subsequent)
None
Integrity (subsequent)
None
Availability (subsequent)
Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.9 CVSS 4.0 Medium — — security-advisories@github.com via NIST National Vulnerability Database
6.9 CVSS 4.0 Medium — — GitHub_M via CVE Program (cve.org) e CISA ADP
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:L/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 (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-233

Other CVEs with this weakness →

EPSS over time FIRST

Oct 23, 2026 → Oct 30, 2026 · 8 reading(s) · max 0.39%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · Received → Deferred
    Oct 23, 2026 · NIST National Vulnerability Database
  • Source status changed · Published → Received
    Oct 23, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 23, 2026
  • CVSS changed · 6.9
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • Record created in this database
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • CVE published
    Oct 23, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 23, 2026 – Oct 23, 2026

References

4 on the record

Elsewhere on this site

Lookyloo
every CVE for this vendor
CWE-233
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-66913 Zip Bomb in Lookyloo Capture Upload Allows Denial of Service Jul 28, 2026
  • CVE-2026-66824 Stored Cross-Site Scripting via Unsafe Capture Tree JSON Embedding Jul 27, 2026
  • CVE-2025-66459 Lookyloo vulnerable to XSS due to unescaped error message passed to innerHTML Dec 2, 2025
  • CVE-2025-66460 Lookyloo vulnerable to XSS due to lack of escaping in HTML elements passed to Datatables Dec 2, 2025
  • CVE-2025-66458 Lookyloo has multiple XSS due to unsafe use of f-strings in Markup Dec 2, 2025
  • CVE-2025-65095 Lookyloo is vulnerable due to improper user input sanitization Nov 19, 2025

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-55835 is "Lookyloo: Potential sub-system DoS due to parameter missmatch in notification", rated Medium. It affects Lookyloo (Lookyloo); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.9 describes technical severity. EPSS 0.39% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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