CVE-2026-100678

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-26. A secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

stoatchat before 0.15.5 fails to enforce account-level attempt limits on MFA login challenges, allowing attackers who know a password to guess TOTP codes with only IP-based rate limiting. Attackers can reuse MFA challenge tickets across multiple failed attempts and distribute guesses across IP addresses to bypass rate limiting and gain account access.

CVSS v3
6.5
EG Score
6.5MEDIUMhigh confidence
EG Risk
45
EG Risk 45/100CISA SSVC

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%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
14th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 26, 2026

Last Modified

September 30, 2026

Advisory Details (2)

Auto-updated Sep 26, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

stoatchat before 0.15.5 MFA Brute Force via Insufficient Rate Limiting | Advisories | VulnCheck

https://www.vulncheck.com/advisories/stoatchat-before-0.15.5-mfa-brute-force-via-insufficient-rate-limiting
github Patch Available🟡 PoC Available

MFA guessing attempts are insufficiently ratelimited · Advisory · stoatchat/stoatchat · GitHub

https://github.com/stoatchat/stoatchat/security/advisories/GHSA-6877-g673-f5r8

Vendor Advisories for CVE-2026-100678(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 24× in last 7d / 29× 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. 2026-10-04 07:47 UTCEG score recompute
  2. 2026-10-04 07:47 UTCGHSA enrichment
  3. 2026-10-03 14:25 UTCEPSS rescore
  4. 2026-10-03 09:58 UTCEG score recompute
  5. 2026-10-03 09:58 UTCGHSA enrichment
  6. 2026-10-02 12:06 UTCEG score recompute
  7. 2026-10-02 12:06 UTCGHSA enrichment
  8. 2026-10-01 19:49 UTCEPSS rescore
  9. 2026-10-01 14:15 UTCGHSA enrichment
  10. 2026-09-30 16:27 UTCEG score recompute
  11. 2026-09-30 16:27 UTCGHSA enrichment
  12. 2026-09-30 15:31 UTCEG score recompute
  13. 2026-09-30 15:31 UTCGHSA enrichment
  14. 2026-09-30 15:02 UTCEPSS rescore
  15. 2026-09-30 12:42 UTCEG score recompute
  16. 2026-09-30 12:42 UTCGHSA enrichment
  17. 2026-09-29 15:20 UTCEPSS rescore
  18. 2026-09-29 14:49 UTCEG score recompute
  19. 2026-09-29 14:49 UTCGHSA enrichment
  20. 2026-09-28 17:00 UTCEG score recompute
  21. 2026-09-28 16:59 UTCGHSA enrichment
  22. 2026-09-28 13:50 UTCEPSS rescore
  23. 2026-09-28 10:10 UTCEG score recompute
  24. 2026-09-28 10:10 UTCGHSA enrichment
  25. 2026-09-27 12:21 UTCEG score recompute
Show 4 more
  1. 2026-09-27 12:21 UTCGHSA enrichment
  2. 2026-09-26 14:32 UTCEG score recompute
  3. 2026-09-26 13:36 UTCEG score recompute
  4. 2026-09-26 13:30 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-100678?
CVE-2026-100678 is a medium vulnerability published on September 26, 2026. stoatchat before 0.15.5 fails to enforce account-level attempt limits on MFA login challenges, allowing attackers who know a password to guess TOTP codes with only IP-based rate limiting. Attackers can reuse MFA challenge tickets across multiple failed attempts and distribute guesses across IP…
When was CVE-2026-100678 disclosed?
CVE-2026-100678 was first published on September 26, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-100678 actively exploited?
CVE-2026-100678 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-100678?
CVE-2026-100678 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-100678?
A fix for CVE-2026-100678 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-100678 are linked in the Vendor Advisories panel on this page.

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