CVE-2026-41431

HIGHNVD 8.08.0—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.0 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 90% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
8.0
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.0Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Zen is a firefox-based browser. Prior to 1.19.9b, Zen Browser ships a Mozilla Application Resource (MAR) updater (org.mozilla.updater) that has had all MAR signature verification stripped from the Firefox codebase it was forked from. The MAR files served to users contain zero cryptographic signatures, and the updater binary contains zero cryptographic verification code. This eliminates the defense-in-depth that MAR signing provides. If the update server or GitHub release pipeline is compromised, arbitrary unsigned code can be delivered to all Zen users via the auto-update mechanism. This vulnerability is fixed in 1.19.9b.

CVSS v3
8.0
EG Score
8.0(medium)
EG Risk
52(Track*)
EG Risk 52/100SSVC: Track*

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
Severity80% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
9.9%
KEV
Not listed

Published

May 11, 2026

Last Modified

May 13, 2026

Advisory Details (2)

Auto-updated May 11, 2026
Patch available. Sources: github.
github Patch Available

Zen Browser MAR updater ships with signature verification removed — unsigned updates accepted · Advisory · zen-browser/desktop · GitHub

https://github.com/zen-browser/desktop/security/advisories/GHSA-qpj9-m8jc-mw6q
generic

Merge commit from fork · zen-browser/desktop@270db6d · GitHub

https://github.com/zen-browser/desktop/commit/270db6d6713d2c6c14d9df0b4bc7662843d3d54e

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 36× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-07-23 14:18 UTCEPSS rescore
  2. 2026-07-23 03:11 UTCEG score recompute
  3. 2026-07-22 14:08 UTCEPSS rescore
  4. 2026-07-21 15:24 UTCEPSS rescore
  5. 2026-07-20 17:08 UTCEPSS rescore
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  9. 2026-07-16 17:03 UTCEPSS rescore
  10. 2026-07-16 03:23 UTCOSV refresh
  11. 2026-07-15 16:57 UTCEPSS rescore
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  19. 2026-07-09 19:10 UTCEPSS rescore
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  21. 2026-07-07 13:46 UTCEPSS rescore
  22. 2026-07-06 16:27 UTCEPSS rescore
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  1. 2026-07-05 02:30 UTCEPSS rescore
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  3. 2026-07-01 15:06 UTCEPSS rescore
  4. 2026-06-30 23:22 UTCEPSS rescore
  5. 2026-06-29 14:06 UTCEPSS rescore
  6. 2026-06-28 14:07 UTCEPSS rescore
  7. 2026-06-28 04:56 UTCEPSS rescore
  8. 2026-06-27 03:08 UTCEPSS rescore
  9. 2026-06-25 13:49 UTCEPSS rescore
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  11. 2026-06-24 14:05 UTCEPSS rescore
  12. 2026-06-23 21:33 UTCEPSS rescore
  13. 2026-06-22 14:25 UTCEPSS rescore
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  15. 2026-06-21 14:56 UTCEPSS rescore
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  17. 2026-06-21 01:59 UTCEPSS rescore
  18. 2026-06-19 19:25 UTCEPSS rescore
  19. 2026-06-18 17:52 UTCEPSS rescore
  20. 2026-06-18 17:52 UTCEPSS rescore
  21. 2026-06-16 17:52 UTCEPSS rescore
  22. 2026-06-15 17:49 UTCEPSS rescore
  23. 2026-06-13 23:00 UTCEPSS rescore
  24. 2026-06-12 23:12 UTCEPSS rescore
  25. 2026-06-12 23:12 UTCEPSS rescore
  26. 2026-06-11 14:00 UTCEPSS rescore
  27. 2026-06-10 22:18 UTCEPSS rescore
  28. 2026-06-10 13:22 UTCEPSS rescore
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  30. 2026-06-08 14:17 UTCEPSS rescore
  31. 2026-06-08 14:17 UTCEPSS rescore
  32. 2026-06-07 15:25 UTCEPSS rescore
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  34. 2026-06-06 13:47 UTCEPSS rescore
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  36. 2026-06-05 22:47 UTCEPSS rescore
  37. 2026-06-05 06:10 UTCEPSS rescore
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  39. 2026-06-04 13:12 UTCEPSS rescore
  40. 2026-06-04 13:12 UTCEPSS rescore
  41. 2026-06-02 20:13 UTCEPSS rescore
  42. 2026-06-01 13:52 UTCEPSS rescore
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  44. 2026-06-01 13:51 UTCEPSS rescore
  45. 2026-05-31 22:30 UTCEPSS rescore
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  47. 2026-05-31 00:16 UTCEPSS rescore
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  49. 2026-05-31 00:16 UTCEPSS rescore
  50. 2026-05-29 13:44 UTCEPSS rescore
  51. 2026-05-29 13:44 UTCEPSS rescore
  52. 2026-05-28 13:44 UTCEPSS rescore
  53. 2026-05-28 13:44 UTCEPSS rescore
  54. 2026-05-28 13:44 UTCEPSS rescore
  55. 2026-05-27 13:40 UTCEPSS rescore
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  58. 2026-05-26 13:44 UTCEPSS rescore
  59. 2026-05-26 07:18 UTCEPSS rescore
  60. 2026-05-26 07:18 UTCEPSS rescore
  61. 2026-05-20 22:38 UTCEPSS rescore
  62. 2026-05-20 22:38 UTCEPSS rescore
  63. 2026-05-20 13:15 UTCEG score recompute
  64. 2026-05-20 11:22 UTCEPSS rescore
  65. 2026-05-20 11:22 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-41431?
CVE-2026-41431 is a high vulnerability published on May 11, 2026. Zen is a firefox-based browser. Prior to 1.19.9b, Zen Browser ships a Mozilla Application Resource (MAR) updater (org.mozilla.updater) that has had all MAR signature verification stripped from the Firefox codebase it was forked from. The MAR files served to users contain zero cryptographic…
When was CVE-2026-41431 disclosed?
CVE-2026-41431 was first published in the National Vulnerability Database on May 11, 2026, with the most recent update on May 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-41431 actively exploited?
CVE-2026-41431 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 9.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-41431?
CVE-2026-41431 has a CVSS v3 base score of 8.0 (NVD).
How do I remediate CVE-2026-41431?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-41431, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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