How severe is CVE-2024-39891?

CVE-2024-39891 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2024-39891 being actively exploited?

Yes. CVE-2024-39891 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2024-07-23, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2024-39891?

CVE-2024-39891 primarily affects Twilio Authy. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2024-39891?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2024-39891 have an EU (EUVD) identifier?

Yes. CVE-2024-39891 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-38291. It is also flagged as exploited in the EUVD (since 2024-07-23).

When was CVE-2024-39891 published?

CVE-2024-39891 was published on 2024-07-02 and last updated on 2026-06-17.

CVE-2024-39891

CVE-2024-39891 is a medium-severity vulnerability in Twilio Authy with a CVSS 3.x base score of 5.3. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2024-07-23). The underlying weakness is classified as CWE-203.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 1% (71st percentile)
Actively exploited: Yes — listed in CISA KEV (added 2024-07-23)
EU (EUVD) id: EUVD-2024-38291
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2024-07-23)
Weakness: CWE-203
Affected product: Twilio Authy
Published: 2024-07-02
Last modified: 2026-06-17

Description

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.)

Frequently asked questions

What is CVE-2024-39891?: 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.)
How severe is CVE-2024-39891?: CVE-2024-39891 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2024-39891 being actively exploited?: Yes. CVE-2024-39891 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2024-07-23, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2024-39891?: CVE-2024-39891 primarily affects Twilio Authy. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-39891?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2024-39891 have an EU (EUVD) identifier?: Yes. CVE-2024-39891 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-38291. It is also flagged as exploited in the EUVD (since 2024-07-23).
When was CVE-2024-39891 published?: CVE-2024-39891 was published on 2024-07-02 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:twilio:authy:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:twilio:authy_authenticator:*:*:*:*:*:android:*:*

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