What is CVE-2020-5753?

CVE-2020-5753 is a medium-severity vulnerability in Signal Private Messenger, classified under Always-Incorrect Control Flow Implementation. CVSS score: 5.3/10. Published 2020-05-20.

How severe is CVE-2020-5753?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Signal Private Messenger

CVE-2020-5753

Signal Private Messenger Android v4.59.0 and up and iOS v3.8.1.5 and up allows a remote non-contact to ring a victim's Signal phone and disclose currently used DNS server due to ICE Candidate handling before call is answered or declined.

Published 2020-05-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.011 (63.7th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 63.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Signal Private Messenger
Signal
Signal Private Messenger — versions Android versions v4.59.0 and up, iOS versions v3.8.1.5 and up

Weakness classification (CWE)

CWE-670 — Always-Incorrect Control Flow Implementation

References

www.tenable.com/security/research/tra-2020-33 (Third Party Advisory)

Frequently asked questions

What is CVE-2020-5753?: CVE-2020-5753 is a medium-severity vulnerability in Signal Private Messenger, classified under Always-Incorrect Control Flow Implementation. CVSS score: 5.3/10. Published 2020-05-20.
How severe is CVE-2020-5753?: Medium severity. CVSS v3 base score is 5.3 out of 10.