CVE-2025-12207VulnerabilityPublished 27 Oct 2025Updated 24 Feb 2026

CVE-2025-12207: Kamailio · NULL Pointer Dereference

Affects KamailioSource CVE Database V5

Not known to be exploited · CVSS 4.8 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

4.8Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Local
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

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

Attack Vector: Local: The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Oct 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 2026-10-26.

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 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
Kamailio	Affected =5.5	Fixed in–

AI-suggested

To mitigate CVE-2025-12207, organizations should implement strict access controls to limit local access to systems running Kamailio, ensuring only trusted administrators can modify configuration files. Employ file integrity monitoring solutions to detect unauthorized changes to Kamailio configuration files promptly. Consider running Kamailio with the least privileges necessary and isolate it within secure environments or containers to reduce the attack surface. Regularly audit user permissions and monitor logs for suspicious local activity. Until an official patch is released, avoid upgrading to or deploying Kamailio 5.5 in environments where local access cannot be tightly controlled. If possible, downgrade to earlier versions not affected by this vulnerability or apply custom patches if available from the community. Maintain up-to-date backups of configuration files to enable quick recovery from potential crashes or misconfigurations. Engage with Kamailio community channels for updates and potential fixes.

Description

A vulnerability has been found in Kamailio 5.5. This affects the function yyerror_at of the file src/core/cfg.y of the component Grammar Rule Handler. Such manipulation leads to null pointer dereference. The attack needs to be performed locally. The exploit has been disclosed to the public and may be used. The actual existence of this vulnerability is currently in question. This attack requires manipulating config files which might not be a realistic scenario in many cases. The vendor was contacted early about this disclosure but did not respond in any way.

Impact

The primary impact of CVE-2025-12207 is on the availability of Kamailio services. A successful exploitation leads to a NULL pointer dereference, causing the Kamailio process to crash and resulting in denial of service. This can disrupt SIP-based communications, affecting VoIP infrastructure, session management, and real-time communication services relying on Kamailio. Since exploitation requires local access and configuration file manipulation, the risk is mitigated in environments with strict access controls. However, in scenarios where local access is possible, such as multi-tenant servers, compromised internal hosts, or insider threats, this vulnerability could be leveraged to cause service outages. The lack of vendor response and patches increases the risk of prolonged exposure. Organizations relying on Kamailio 5.5 for critical communications may experience service interruptions, impacting business operations and customer communications.

Summary

CVE-2025-12207 is a vulnerability identified in Kamailio version 5.5, specifically within the Grammar Rule Handler component's yyerror_at function located in the src/core/cfg.y source file. The issue arises from a NULL pointer dereference triggered by improper handling of configuration file inputs. When an attacker with local access manipulates the configuration files, the function may dereference a NULL pointer, causing the Kamailio process to crash or behave unpredictably. This vulnerability does not require user interaction or elevated privileges beyond local access, but the attack vector is constrained by the necessity to modify configuration files, which are typically protected and require some level of privilege. The vulnerability has a CVSS 4.8 score, reflecting its medium severity, with an attack vector classified as local and low complexity. No authentication or user interaction is needed, but the scope is limited to local privilege. The vendor has not issued any patches or advisories, and the exploit has been publicly disclosed, though the actual existence and exploitability have been questioned. The primary impact is denial of service due to service crashes, potentially disrupting SIP communications managed by Kamailio.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Feb 2026, 21:35 UTC

Technical details

References

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