Description
The Signal app before 5.34 for iOS allows URI spoofing via RTLO injection. It incorrectly renders RTLO encoded URLs beginning with a non-breaking space, when there is a hash character in the URL. This technique allows a remote unauthenticated attacker to send legitimate looking links, appearing to be any website URL, by abusing the non-http/non-https automatic rendering of URLs. An attacker can spoof, for example, example.com, and masquerade any URL with a malicious destination. An attacker requires a subdomain such as gepj, txt, fdp, or xcod, which would appear backwards as jpeg, txt, pdf, and docx respectively.
References (4)
Core 4
Core References
Exploit, Patch, Third Party Advisory x_refsource_misc
https://sick.codes/sick-2022-42
Exploit, Patch, Third Party Advisory x_refsource_misc
https://github.com/sickcodes/security/blob/master/advisories/SICK-2022-42.md
Third Party Advisory x_refsource_misc
https://blog.malwarebytes.com/social-engineering/2022/03/uri-spoofing-flaw-could-phish-whatsapp-signal-instagram-and-imessage-users/
Scores
CVSS v3
7.5
EPSS
0.0108
EPSS Percentile
77.9%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Details
CWE
CWE-74
Status
published
Products (1)
signal/signal
< 5.34
Published
Apr 15, 2022
Tracked Since
Feb 18, 2026