VulnerabilityPublished 26 Nov 2025

CVE-2025-64129: Zenitel TCIV-3+ · Out-of-bounds Write

Affects Zenitel TCIV-3+Source CVE Database V5

Not known to be exploited · CVSS 7.6 High.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score

7.6High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Zenitel TCIV-3+	Affected =0	Fixed in–

AI-suggested

Immediately implement strict network segmentation to isolate Zenitel TCIV-3+ devices from untrusted or public networks, limiting exposure to potential attackers.
Restrict remote access to these devices using firewalls and VPNs with strong authentication to prevent unauthorized connections.
Monitor network traffic and device logs for unusual activity or signs of exploitation attempts, employing intrusion detection systems tailored for OT environments.
Educate users and administrators about the requirement for user interaction in exploitation to reduce inadvertent triggering of the vulnerability.
Maintain an inventory of all affected devices and prioritize them for monitoring and mitigation efforts.
Engage with Zenitel support channels to obtain updates on patch availability and apply vendor patches promptly once released.
Consider deploying temporary compensating controls such as disabling unnecessary services or features on the devices to reduce attack vectors.
Develop and test incident response plans specific to potential denial-of-service events affecting communication devices.

Description

CVE-2025-64129 is a high-severity out-of-bounds write vulnerability (CWE-787) affecting the Zenitel TCIV-3+ intercom device. This flaw allows a remote attacker to cause a denial-of-service by crashing the device without requiring authentication, though user interaction is needed. The vulnerability impacts confidentiality, integrity, and availability, with the most significant effect being availability due to device crashes. No known exploits are currently reported in the wild, and no patches have been released yet. European organizations using Zenitel TCIV-3+ devices, especially in critical infrastructure or industrial environments, could face operational disruptions. Mitigation should focus on network segmentation, restricting remote access, monitoring device behavior, and preparing for vendor patches. Countries with higher adoption of Zenitel products and critical infrastructure reliance on such intercom systems, such as Germany, France, the UK, and the Netherlands, are more likely to be affected. Given the ease of remote exploitation and impact on availability, this vulnerability is rated as high severity.

Impact

For European organizations, this vulnerability poses a significant risk to operational continuity, especially in sectors relying on Zenitel TCIV-3+ devices for secure communication, such as manufacturing, transportation, energy, and public safety. A successful exploitation could lead to denial-of-service conditions, disrupting communication channels critical for safety and operational coordination. The limited impact on confidentiality and integrity reduces the risk of data breaches but does not eliminate concerns about potential memory corruption side effects. The lack of authentication requirement and remote exploitability increase the attack surface, particularly if devices are exposed to untrusted networks or insufficiently segmented environments. Disruptions could lead to operational downtime, safety hazards, and financial losses. The absence of patches necessitates proactive defensive measures to mitigate risks until vendor updates are available.

Summary

CVE-2025-64129 identifies a critical out-of-bounds write vulnerability (CWE-787) in the Zenitel TCIV-3+ intercom device. This vulnerability allows a remote attacker to write data outside the intended buffer boundaries, which can corrupt memory and lead to device crashes. The flaw can be triggered remotely over the network without requiring any privileges, although it requires some form of user interaction to exploit. The vulnerability primarily threatens the availability of the device by causing denial-of-service conditions, but it also has limited impact on confidentiality and integrity due to potential memory corruption. The CVSS v3.1 score of 7.6 reflects the high risk posed by this vulnerability, considering its network attack vector, low attack complexity, no privileges required, but requiring user interaction. Currently, there are no known exploits in the wild, and no patches have been released by Zenitel, increasing the urgency for organizations to implement interim mitigations. The affected product, TCIV-3+, is commonly used in industrial and critical communication environments, making the vulnerability particularly concerning for operational technology (OT) networks. The vulnerability was reserved in late October 2025 and published in November 2025, indicating recent discovery and disclosure.

CWE-787Out-of-bounds Write (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #5
The product writes data past the end, or before the beginning, of the intended buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Dec 2025, 18:58 UTC

WeaknessesCWE-787

Technical details

References

Community reviews

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