Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2024-39891

Authy

Twilio / Authy · affected before 26.1.0

Watch CVE-2024-39891 Browse KEV feed
Severity
CVSS 5.3 · Medium
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
1.7%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2024-39891 is an unauthenticated vulnerability affecting Twilio Authy. 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...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV.

Who is affected?

Twilio / Authy affected before 26.1.0.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Authy

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.)

twilio Affected
authy_2-factor_authentication
Before 26.1.0 Before 25.1.0
Published
02 Jul 2024
Exploitation Reported
23 Jul 2024
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

ios android cisa

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 23 Jul 2024

A trusted third party reported exploitation.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
CISA First 2024-07-23 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

5.3 Medium

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AC:L/AV:N/A:N/C:L/I:N/PR:N/S:U/UI:N

EPSS

1.7%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Observable Discrepancy CWE-203

Timeline

From disclosure to observed exploitation

  1. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  2. 00:00 UTC

    CVE published

    Vulnerability disclosed publicly

  3. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2024-39891

Sample API response 
{
  "cve_id": "CVE-2024-39891",
  "confidence": "Confirmed",
  "cvss_score": 5.3,
  "cvss_estimated": false,
  "epss_score": 0.01669,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}