Yealink IP Phones and RPS (Redirect and Provisioning Service)

2025-08-07 14:00 (CEST) US CERT (ICS)

Yealink IP Phones and RPS (Redirect and Provisioning Service)

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1. EXECUTIVE SUMMARY

CVSS v4 5.3
ATTENTION: Exploitable remotely/Low attack complexity
Vendor: Yealink
Equipment: IP Phones
Vulnerability: Improper Restriction of Excessive Authentication Attempts, Allocation of Resources Without Limits or Throttling, Incorrect Authorization, Improper Certificate Validation

2. RISK EVALUATION
Successful exploitation of these vulnerabilities could result in an information disclosure.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of Yealink IP products are affected:

SIP-T19P_E2: Versions prior to 53.84.0.121
SIP-T21P_E2: Versions prior to 52.84.0.121
SIP-T23G: Versions prior to 44.84.0.121
SIP-T40G: Versions prior to 76.84.0.121
SIP-T40P: Versions prior to 54.84.0.121
SIP-T27G: Versions prior to 69.84.0.121
SIP-T41S: Versions prior to 66.84.0.121
SIP-T42S: Versions prior to 66.84.0.121
SIP-T46S: Versions prior to 66.84.0.121
SIP- T48S: Versions prior to 66.84.0.121
SIP-CP920: Versions prior to 78.84.0.121
SIP-T53: Versions prior to X.84.0.121
SIP-T53W: Versions prior to X.84.0.121
SIP-T54W: Versions prior to X.84.0.121
SIP-T57W: Versions prior to X.84.0.121
SIP-T56A: Versions prior to 58.84.0.37
SIP-T58: Versions prior to 58.84.0.37
W52P: Versions prior to 25.81.0.67
W60B: Versions prior to 77.83.0.83
CP960: Versions prior to 73.84.0.37
SIP-T27P: Version 45.83.0.160 and prior
SIP-T29G: Version 46.83.0.160 and prior
SIP-T41P: Version 36.83.0.160 and prior
SIP-T42G: Version 29.83.0.160 and prior
SIP-T46G: Version 28.83.0.160 and prior
SIP-T48G: Version 35.83.0.160 and prior
SIP-T20P: All versions
SIP-T22P: All versions
SIP-T26P: All versions
SIP-T27P: All versions
T52S: All versions
T54S: All versions
RPS (Redirect and Provisioning Service): All builds prior to 05-26-2025

3.2 VULNERABILITY OVERVIEW
3.2.1 IMPROPER RESTRICTION OF EXCESSIVE AUTHENTICATION ATTEMPTS CWE-307
The affected products lack serial number verification attempt limits, enabling brute-force enumeration (last five digits).
CVE-2025-52916 has been assigned to this vulnerability. A CVSS v3 base score of 2.2 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N).
A CVSS v4 score has also been calculated for CVE-2025-52916. A base score of 2.1 has been calculated; the CVSS vector string is (AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N).
3.2.2 ALLOCATION OF RESOURCES WITHOUT LIMITS OR THROTTLING CWE-770
The affected products lack rate limiting, potentially enabling information disclosure via excessive requests.
CVE-2025-52917 has been assigned to this vulnerability. A CVSS v3 base score of 4.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N).
A CVSS v4 score has also been calculated for CVE-2025-52917. A base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N).
3.2.3 INCORRECT AUTHORIZATION CWE-863
The affected products fail to enforce access restrictions on OpenAPIs for frozen enterprise accounts, allowing unauthorized access to deactivated interfaces.
CVE-2025-52918 has been assigned to this vulnerability. A CVSS v3 base score of 5.0 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N).
A CVSS v4 score has also been calculated for CVE-2025-52918. A base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N).
3.2.4 IMPROPER CERTIFICATE VALIDATION CWE-295
The certificate upload function in the affected products does not properly validate certificate content, potentially allowing invalid certificates to be uploaded.
CVE-2025-52919 has been assigned to this vulnerability. A CVSS v3 base score of 4.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N).
A CVSS v4 score has also been calculated for CVE-2025-52919. A base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:L/SI:N/SA:N).
3.3 BACKGROUND

CRITICAL INFRASTRUCTURE SECTORS: Communications
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: China

3.4 RESEARCHER
Jeroen Hermans of CloudAware reported these vulnerabilities to CISA.
4. MITIGATIONS
Users of Yealink are encouraged to navigate to Yealink's support portal and update to the following versions:

SIP-T19P_E2: Version 53.84.0.160 or higher
SIP-T21P_E2: Version 52.84.0.160 or higher
SIP-T23G: Version 44.84.0.160 or higher
SIP-T40G: Version 76.84.0.160 or higher
SIP-T40P: Version 54.84.0.160 or higher
SIP-T27G: Version 69.86.0.160 or higher
SIP-T41S: Version 66.86.0.83 or higher
SIP-T42S: Version 66.86.0.83 or higher
SIP-T46S: Version 66.86.0.83 or higher
SIP- T48S: Version 66.86.0.83 or higher
SIP-CP920: Version 78.86.0.15 or higher
SIP-T53: Version 96.86.0.75 or higher
SIP-T53W: Version 96.86.0.75 or higher
SIP-T54W: Version 96.86.0.75 or higher
SIP-T57W: Version 96.86.0.75 or higher
SIP-T56A: Version 58.86.0.160 or higher
SIP-T58: Version 58.86.0.160 or higher
W52P: Version 25.81.0.160 or higher
W60B: Version 77.85.0.160 or higher
CP960: Version 73.86.0.160 or higher
SIP-T27P: Version 45.83.0.161 or higher
SIP-T29G: Version 46.83.0.160 and prior
SIP-T41P: Version 36.83.0.160 and prior
SIP-T42G: Version 29.83.0.160 and prior
SIP-T46G: Version 28.83.0.160 and prior
SIP-T48G: Version 35.83.0.160 and prior
RPS (Redirect and Provisioning Service): Yealink has deployed a fix to all cloud service instances

The following products are no longer receiving RPS support:

SIP-T20P
SIP-T22P
SIP-T26P
SIP-T27P
T52S
T54S

For more information, see the associated Yealink security advisory: Yealink RPS Issue Statement.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:

Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.
5. UPDATE HISTORY

August 07, 2025: Initial Publication

https://www.cisa.gov/news-events/ics-advisories/icsa-25-219-08