vciy

CVE-2024-39891

INDEX BUILT · 2026-09-20

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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…

CVE-2024-398913 of 4 sources documented this
65

rank 65 = 40 + 13 + 2 + 4 + 6

rank@v1 · this cycle

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.01669 · CISA KEV listed  ·  without this subject the record ranks 25

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 5.3, from NVD  ·  without this subject the record ranks 52

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

rose on 2025-11-18  ·  without this subject the record ranks 63

How much of the world it touches

NVD CPE configurations

2 products in the CPE ranges  ·  without this subject the record ranks 61

Someone else already set the date

CISA KEV remediation due date

CISA remediation date held  ·  without this subject the record ranks 59

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$20,000over the next 30 days, if this record is yours
Movement-$133,000on 2025-03-30, the last material move, 1 year, 5 months before this reading
Basisassumeda published average, not your estate

$20,000 = $4.99M incident cost x 0.24048551839932833 exposure x 0.01669 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.01669EPSSKEV · LISTED
Severity5.3 MEDIUMreceipt
Harmunauthenticated · networkreceipt
Exploitationin the wild · KEVreceipt
Defenseunaffected versions publishedreceipt
Movementdoubled within 72hreceipt
PLATEAU10Minimal movement since 2026-06-15, 81 days at 0.02, as of 2026-09-04. arc-rules@v1

Foresight · where to check next

No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.

Color is a claim, not decoration:the hostile worldthe defenseno signal

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Harm, if it fires from the vector and the weakness

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Reachnetwork-reachable · no privileges required · no user interaction · low attack complexityreceipt
ImpactPartial confidentiality lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-203 Observable Discrepancyreceipt
Published consequencesCWE-203: Confidentiality, Access Control: Read Application Data, Bypass Protection Mechanism; Confidentiality: Read Application Data[email protected]
Ransomware campaign useUnknown to CISAreceipt

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

First unaffected version, by branchauthy 26.1.0; authy authenticator 25.1.0receipt
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.
CISA remediation statusoverdue since 2024-08-13receipt
CISA required actionApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.receipt
Published to CISA KEV21 daysderived

Exploit Status & Known PoCs a ladder, not a score

Current rung: Exploited in the wild · CISA KEV listed, 2024-07-23.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published
  • RUNG 3Exploited in the wild · CISA KEV listed2024-07-23receipt
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, the CNA5.3 MEDIUMreceipt
CVSS, NVD5.3 MEDIUMreceipt
Exploit probability0.01669 · top 24% of all CVEsreceipt
Blast breadth2 products across 1 vendorderived
Assigned bymitrereceipt
Recorded changes35 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Named in the CPE rangesTwilio authy; Twilio authy authenticatorreceipt
Published rangestwilio authy < 26.1.0; twilio authy authenticator < 25.1.0receipt

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

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What it is stated by the CNA

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.) receipt

NVD's analysis a second authority

severity
5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
weakness
CWE-203
affected versions
twilio authy < 26.1.0; twilio authy authenticator < 25.1.0
also scored by
[email protected] 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

check it yourself cwe.mitre.org twilio.com twilio.com bleepingcomputer.com receipt

Dated events

2024-07-23Added to CISA KEV2024-07-25EPSS moved 0.00 to 0.122024-08-13CISA remediation due2025-04-15EPSS moved 0.40 to 0.182026-06-15EPSS moved 0.17 to 0.01

Movement the material steps

3 Jul 20240.00045
25 Jul 20240.11792 · crossed 0.10
17 Mar 20250.30853 · scoring model v2025.03.14
29 Mar 20250.51359 · crossed 0.50
30 Mar 20250.40274 · crossed 0.50
15 Apr 20250.18149
1 Sep 20250.30621
28 Apr 20260.17066
15 Jun 20260.01477 · crossed 0.10 · scoring model v2026.06.15
18 Aug 20260.01669

This score more than doubled inside 72 hours. Both observations are in the full history below.

Show all 24 observations
3 Jul 20240.00045
24 Jul 20240.00177
25 Jul 20240.11792
17 Oct 20240.13638
4 Nov 20240.18994
19 Nov 20240.19957
17 Mar 20250.30853
18 Mar 20250.33897
28 Mar 20250.40274
29 Mar 20250.51359
30 Mar 20250.40274
15 Apr 20250.18149
10 Aug 20250.27731
11 Aug 20250.26824
1 Sep 20250.30621
22 Oct 20250.30961
6 Nov 20250.20731
18 Nov 20250.34809
21 Nov 20250.24538
4 Dec 20250.23189
7 Feb 20260.29582
28 Apr 20260.17066
15 Jun 20260.01477
18 Aug 20260.01669

24 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.01669Published2024-07-02CISA KEV2024-07-23Index as of2026-09-04

Listed by CISA 21 days after it published, exploit probability more than doubled between 2024-07-24 and 2024-07-25 (0.00177 → 0.11792) and the record had been public for 2 years, 2 months when this index was last written.

No material movement in 17 days as of the last ingest this index recorded.

Published 2024-07-02 receipt · CISA KEV 2024-07-23 receipt · Index as of 2026-09-04 derived

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