CVE-2026-8683

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-06-15. a secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0

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

Mattermost Desktop App versions <=6.1 5.5.13.0 fail to account for attempting to open extremely long URLs in the Mattermost Desktop App which allows a malicious server owner to crash the application via including a script to call window.open on a very large URL. Mattermost Advisory ID: MMSA-2026-00652

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
34(Track)
EG Risk 34/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
10.0%
KEV
Not listed

Published

June 15, 2026

Last Modified

June 16, 2026

Advisory Details (1)

Auto-updated Jun 15, 2026
No patch confirmed yet.
generic

Security Updates

https://mattermost.com/security-updates

Vendor Advisories for CVE-2026-8683(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 55× 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. 2026-07-24 14:18 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:23 UTCEG score recompute
  4. 2026-07-22 14:08 UTCEPSS rescore
  5. 2026-07-21 15:25 UTCEPSS rescore
  6. 2026-07-21 15:25 UTCEPSS rescore
  7. 2026-07-20 17:08 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 02:29 UTCEPSS rescore
  10. 2026-07-18 10:04 UTCEPSS rescore
  11. 2026-07-16 22:58 UTCGHSA enrichment
  12. 2026-07-16 17:03 UTCEPSS rescore
  13. 2026-07-15 15:49 UTCGHSA enrichment
  14. 2026-07-15 02:00 UTCEPSS rescore
  15. 2026-07-14 10:22 UTCGHSA enrichment
  16. 2026-07-13 22:31 UTCEPSS rescore
  17. 2026-07-13 06:13 UTCEPSS rescore
  18. 2026-07-13 05:57 UTCGHSA enrichment
  19. 2026-07-12 05:46 UTCEPSS rescore
  20. 2026-07-12 04:38 UTCGHSA enrichment
  21. 2026-07-11 08:27 UTCEPSS rescore
  22. 2026-07-11 03:52 UTCGHSA enrichment
  23. 2026-07-10 03:08 UTCGHSA enrichment
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-09 02:24 UTCGHSA enrichment
Show 49 more
  1. 2026-07-08 15:16 UTCEPSS rescore
  2. 2026-07-08 01:12 UTCGHSA enrichment
  3. 2026-07-07 13:46 UTCEPSS rescore
  4. 2026-07-07 00:24 UTCGHSA enrichment
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 16:27 UTCEPSS rescore
  7. 2026-07-06 02:23 UTCEPSS rescore
  8. 2026-07-06 02:23 UTCEPSS rescore
  9. 2026-07-05 10:48 UTCGHSA enrichment
  10. 2026-07-05 02:31 UTCEPSS rescore
  11. 2026-07-05 02:30 UTCEPSS rescore
  12. 2026-07-04 10:05 UTCGHSA enrichment
  13. 2026-07-04 06:31 UTCEPSS rescore
  14. 2026-07-04 06:31 UTCEPSS rescore
  15. 2026-07-03 07:19 UTCGHSA enrichment
  16. 2026-07-02 05:25 UTCGHSA enrichment
  17. 2026-07-01 15:07 UTCEPSS rescore
  18. 2026-07-01 04:42 UTCGHSA enrichment
  19. 2026-06-30 23:22 UTCEPSS rescore
  20. 2026-06-30 03:56 UTCGHSA enrichment
  21. 2026-06-29 14:06 UTCEPSS rescore
  22. 2026-06-29 03:13 UTCGHSA enrichment
  23. 2026-06-28 14:07 UTCEPSS rescore
  24. 2026-06-28 04:56 UTCEPSS rescore
  25. 2026-06-28 02:30 UTCGHSA enrichment
  26. 2026-06-27 03:08 UTCEPSS rescore
  27. 2026-06-27 01:46 UTCGHSA enrichment
  28. 2026-06-26 01:03 UTCGHSA enrichment
  29. 2026-06-25 13:50 UTCEPSS rescore
  30. 2026-06-25 00:14 UTCGHSA enrichment
  31. 2026-06-24 14:05 UTCEPSS rescore
  32. 2026-06-23 23:23 UTCGHSA enrichment
  33. 2026-06-23 21:33 UTCEPSS rescore
  34. 2026-06-22 22:39 UTCGHSA enrichment
  35. 2026-06-22 14:25 UTCEPSS rescore
  36. 2026-06-21 21:57 UTCGHSA enrichment
  37. 2026-06-21 14:56 UTCEPSS rescore
  38. 2026-06-21 01:59 UTCEPSS rescore
  39. 2026-06-20 20:16 UTCGHSA enrichment
  40. 2026-06-19 19:26 UTCEPSS rescore
  41. 2026-06-19 19:04 UTCGHSA enrichment
  42. 2026-06-18 18:16 UTCGHSA enrichment
  43. 2026-06-18 17:52 UTCEPSS rescore
  44. 2026-06-17 17:53 UTCEPSS rescore
  45. 2026-06-17 17:33 UTCGHSA enrichment
  46. 2026-06-16 17:53 UTCEPSS rescore
  47. 2026-06-16 16:49 UTCGHSA enrichment
  48. 2026-06-15 16:04 UTCEG score recompute
  49. 2026-06-15 16:03 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-8683?
CVE-2026-8683 is a medium vulnerability published on June 15, 2026. Mattermost Desktop App versions <=6.1 5.5.13.0 fail to account for attempting to open extremely long URLs in the Mattermost Desktop App which allows a malicious server owner to crash the application via including a script to call window.open on a very large URL. Mattermost Advisory ID:…
When was CVE-2026-8683 disclosed?
CVE-2026-8683 was first published in the National Vulnerability Database on June 15, 2026, with the most recent update on June 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8683 actively exploited?
CVE-2026-8683 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 10.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-8683?
CVE-2026-8683 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-8683?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8683, 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.

Dependency Blast Radius

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