CVE-2026-66913

MEDIUMPre-NVD 6.96.9
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (35th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
6.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 6.9Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

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.

CVSS v3
6.9
EG Score
6.9MEDIUMmedium confidence
EG Risk
31
EG Risk 31/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity69% × 45%
The EG Score, 6.9 of 10.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.
EPSS PROB
0.4%
EPSS %ILE
35th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 28, 2026

Last Modified

July 30, 2026

Advisory Details (1)

Auto-updated Jul 28, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
GitHub commit

commit 96589da290f0 (Lookyloo/lookyloo)

Fix landed in Lookyloo/lookyloo commit 96589da290f0 — awaiting tagged release

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

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 40× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 116 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 17 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  2. 2026-10-12 15:46 UTCEG score recompute
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  6. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 35th percentile
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  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 34th percentile
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  1. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  2. 2026-09-25 06:18 UTCEG score recompute
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  4. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 17th percentile
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  9. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 17th percentile
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  18. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 16th percentile
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  45. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 17th percentile
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Frequently asked(5)

What is CVE-2026-66913?
CVE-2026-66913 is a medium-severity vulnerability; its CVE record was published on July 28, 2026. 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…
When was the CVE record for CVE-2026-66913 published?
The CVE record for CVE-2026-66913 was published on July 28, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of July 30, 2026; the record at its source may have been updated since.
Is CVE-2026-66913 actively exploited?
CVE-2026-66913 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (35th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66913?
CVE-2026-66913 has a CVSS base score of 6.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-66913?
An upstream fix for CVE-2026-66913 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix.

Dependency Blast Radius

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