CVE-2025-55177
Meta Platforms WhatsApp Incorrect Authorization Vulnerability
Meta Platforms WhatsApp
Incomplete authorization of linked device synchronization messages in WhatsApp for iOS prior to v2.25.21.73, WhatsApp Business for iOS v2.25.21.78, and WhatsApp for Mac v2.25.21.78 could have allowed an unrelated user to trigger processing of content from an arbitrary URL on a target’s device. We assess that this vulnerability, in combination with an OS-level vulnerability on Apple platforms (CVE-2025-43300), may have been exploited in a sophisticated attack against specific targeted users.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 2 September 2025. US federal agencies were required to remediate it by 23 September 2025.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 13.5%, which is higher than 96.5% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Frequently asked questions
Is CVE-2025-55177 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2025-55177.
What does CVE-2025-55177 affect?
CVE-2025-55177 affects Meta Platforms WhatsApp. Incomplete authorization of linked device synchronization messages in WhatsApp for iOS prior to v2.25.21.73, WhatsApp Business for iOS v2.25.21.78, and WhatsApp for Mac v2.25.21.78 could have allowed an unrelated user to trigger processing of content from an arbitrary URL on a target’s device. We assess that this vulnerability, in combination with an OS-level vulnerability on Apple platforms (CVE-2025-43300), may have been exploited in a sophisticated attack against specific targeted users.
How severe is CVE-2025-55177?
CVE-2025-55177 is rated MEDIUM with a CVSS base score of 5.4. EPSS puts the probability of exploitation in the next 30 days at 13.5%, higher than 96.5% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 23 September 2025.
How should organisations respond to CVE-2025-55177?
Apply the vendor patch for Meta Platforms WhatsApp as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.