In the Twilio Authy API, accessed by Authy Android before 25.1.0 and Authy iOS before 26.1.0, an unauthenticated endpoint provided access to certain phone-number data, as exploited in the wild in June 2024. Specifically, the endpoint accepted a stream of requests containing phone numbers, and responded with information about whether each phone number was registered with Authy. (Authy accounts were not compromised, however.)
CVE-2024-39891
Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2024-07-23), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 5.3 retained for reference. Confidence: HIGH.
- Actively exploited in the wild (CISA-KEV)
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.3
- EG Score
- 9.0(high)
- EG Risk
- 96(Attend)EG Risk 96/100SSVC: Attend
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 computedSeverity90% × 45%Exploitation100% × 40%Automatability100% × 15%Action: Remediate soon — notable exploitation risk. - EPSS
- 71.2%
- KEV
- ⚠ Exploited
Published
July 2, 2024
Last Modified
November 5, 2025
Advisory Details (5)
Auto-updated Jun 13, 2026Known Exploited Vulnerabilities Catalog | CISA
Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-39891Reporting Security Vulnerabilities | Twilio
https://www.twilio.com/docs/usage/security/reporting-vulnerabilitiesHackers abused API to verify millions of Authy MFA phone numbers
https://www.bleepingcomputer.com/news/security/hackers-abused-api-to-verify-millions-of-authy-mfa-phone-numbers/Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 53× in last 7d / 234× 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.
Showing the most recent 100 of 451 total refreshes for this CVE.
- 2026-07-24 14:16 UTCEPSS rescore
- 2026-07-23 14:17 UTCEPSS rescore
- 2026-07-23 14:17 UTCEPSS rescore
- 2026-07-23 02:38 UTCEG score recompute
- 2026-07-22 23:12 UTCEG score recompute
- 2026-07-22 23:11 UTCGHSA enrichment
- 2026-07-22 19:40 UTCCISA KEV update
- 2026-07-22 19:14 UTCGHSA enrichment
- 2026-07-22 15:18 UTCEG score recompute
- 2026-07-22 15:18 UTCGHSA enrichment
- 2026-07-22 14:07 UTCEPSS rescore
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- 2026-07-22 11:20 UTCGHSA enrichment
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- 2026-07-22 03:29 UTCGHSA enrichment
- 2026-07-21 23:33 UTCGHSA enrichment
- 2026-07-21 19:37 UTCGHSA enrichment
- 2026-07-21 15:39 UTCEG score recompute
- 2026-07-21 15:39 UTCGHSA enrichment
- 2026-07-21 15:23 UTCEPSS rescore
- 2026-07-21 15:23 UTCEPSS rescore
- 2026-07-21 14:37 UTCCISA KEV update
- 2026-07-21 11:44 UTCGHSA enrichment
- 2026-07-21 07:47 UTCGHSA enrichment
- 2026-07-21 03:52 UTCGHSA enrichment
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- 2026-07-20 23:56 UTCGHSA enrichment
- 2026-07-20 20:00 UTCEG score recompute
- 2026-07-20 20:00 UTCGHSA enrichment
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- 2026-07-20 16:04 UTCGHSA enrichment
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- 2026-07-19 20:22 UTCGHSA enrichment
- 2026-07-19 16:26 UTCEG score recompute
- 2026-07-19 16:26 UTCGHSA enrichment
- 2026-07-19 14:30 UTCEPSS rescore
- 2026-07-19 14:30 UTCEPSS rescore
- 2026-07-19 12:30 UTCGHSA enrichment
- 2026-07-19 08:32 UTCGHSA enrichment
- 2026-07-19 04:36 UTCEG score recompute
- 2026-07-19 04:36 UTCGHSA enrichment
- 2026-07-19 02:28 UTCEPSS rescore
- 2026-07-19 02:28 UTCEPSS rescore
- 2026-07-19 00:40 UTCGHSA enrichment
- 2026-07-18 20:43 UTCGHSA enrichment
- 2026-07-18 16:47 UTCGHSA enrichment
- 2026-07-18 12:52 UTCEG score recompute
- 2026-07-18 12:51 UTCGHSA enrichment
- 2026-07-18 10:03 UTCEPSS rescore
- 2026-07-18 08:56 UTCGHSA enrichment
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- 2026-07-17 21:07 UTCGHSA enrichment
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- 2026-07-17 13:16 UTCGHSA enrichment
- 2026-07-17 09:20 UTCEG score recompute
- 2026-07-17 09:20 UTCGHSA enrichment
- 2026-07-17 05:24 UTCGHSA enrichment
- 2026-07-17 01:28 UTCGHSA enrichment
- 2026-07-16 21:33 UTCGHSA enrichment
- 2026-07-16 17:38 UTCGHSA enrichment
- 2026-07-16 17:04 UTCCISA KEV update
- 2026-07-16 17:02 UTCEPSS rescore
- 2026-07-16 13:42 UTCGHSA enrichment
- 2026-07-16 09:47 UTCGHSA enrichment
- 2026-07-16 05:51 UTCGHSA enrichment
- 2026-07-16 01:55 UTCGHSA enrichment
- 2026-07-15 21:59 UTCGHSA enrichment
- 2026-07-15 18:03 UTCGHSA enrichment
- 2026-07-15 16:56 UTCEPSS rescore
- 2026-07-15 16:56 UTCEPSS rescore
- 2026-07-15 16:49 UTCCISA KEV update
- 2026-07-15 15:04 UTCCISA KEV update
- 2026-07-15 14:08 UTCGHSA enrichment
- 2026-07-15 10:12 UTCGHSA enrichment
- 2026-07-15 06:16 UTCGHSA enrichment
- 2026-07-15 02:20 UTCGHSA enrichment
- 2026-07-15 01:59 UTCEPSS rescore
- 2026-07-15 01:59 UTCEPSS rescore
- 2026-07-14 22:24 UTCGHSA enrichment
- 2026-07-14 18:28 UTCGHSA enrichment
- 2026-07-14 18:05 UTCCISA KEV update
- 2026-07-14 14:32 UTCGHSA enrichment
- 2026-07-14 10:37 UTCGHSA enrichment
- 2026-07-14 06:37 UTCGHSA enrichment
- 2026-07-14 02:41 UTCGHSA enrichment
- 2026-07-13 22:46 UTCGHSA enrichment
- 2026-07-13 22:29 UTCEPSS rescore
- 2026-07-13 18:51 UTCGHSA enrichment
- 2026-07-13 17:07 UTCCISA KEV update
- 2026-07-13 14:55 UTCGHSA enrichment
- 2026-07-13 10:59 UTCGHSA enrichment
- 2026-07-13 07:03 UTCGHSA enrichment
- 2026-07-13 06:11 UTCEPSS rescore
- 2026-07-13 03:05 UTCGHSA enrichment
- 2026-07-12 23:10 UTCGHSA enrichment
- 2026-07-12 19:14 UTCGHSA enrichment
- 2026-07-12 15:18 UTCGHSA enrichment
- 2026-07-12 11:22 UTCGHSA enrichment
Frequently asked(6)
What is CVE-2024-39891?
When was CVE-2024-39891 disclosed?
Is CVE-2024-39891 actively exploited?
What is the CVSS score of CVE-2024-39891?
Which products are affected by CVE-2024-39891?
How do I remediate CVE-2024-39891?
Dependency Blast Radius
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