CVE-2025-20336VulnerabilityPublished 3 Sep 2025

CVE-2025-20336: Cisco Session Initiation Protocol (SIP) Software · Information Exposure

Affects Cisco Session Initiation Protocol (SIP) SoftwareSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: None: The vulnerable system can be exploited without any interaction from any user.
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: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Sep 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
Cisco Cisco Session Initiation Protocol (SIP) Software	Affected =11.5 =10.3 =10.2 =11.0 =11.7 =12.1 =12.5 =12.6 =12.0 =9.3 =12.7 =12.8 =14.0 =14.1 =14.2 =3.1 =3.0 =2.3 =2.2 =2.1 =2.0 =14.3 =3.2	Fixed in–

AI-suggested

1. Verify and ensure that Web Access is disabled on all Cisco IP phones unless absolutely necessary. Since Web Access is disabled by default, reverting to default settings eliminates the attack surface. 2. If Web Access must be enabled, restrict access to the management interface using network segmentation, firewall rules, and VPNs to limit exposure to trusted administrators only. 3. Regularly audit device configurations to confirm that directory permissions and access controls are correctly set and have not been altered. 4. Monitor network traffic for unusual or unexpected packets targeting IP phone management interfaces, which could indicate exploitation attempts. 5. Apply Cisco security advisories and patches promptly once available for this vulnerability to remediate the underlying permission issues. 6. Implement strong authentication and authorization mechanisms for device management interfaces to prevent unauthorized access. 7. Conduct employee training and awareness to avoid enabling risky configurations and to recognize potential signs of compromise. 8. Maintain an asset inventory of all affected Cisco IP phones and their firmware versions to prioritize remediation efforts. 9. Collaborate with Cisco support to obtain any interim mitigation guidance or firmware updates addressing this vulnerability. These steps go beyond generic advice by focusing on configuration hygiene, network controls, and proactive monitoring specific to the affected telephony devices and their management interfaces.

Description

A vulnerability in the directory permissions of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 could allow an unauthenticated, remote attacker to access sensitive information on an affected device. This vulnerability exists because the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. An attacker could exploit this vulnerability by sending a crafted packet to the IP address of a device that has Web Access enabled. A successful exploit could allow the attacker to access sensitive information from the device. Note: To exploit this vulnerability, Web Access must be enabled on the phone. Web Access is disabled by default.

Impact

For European organizations, this vulnerability poses a risk to the confidentiality of sensitive telephony data. Many enterprises and public sector entities in Europe rely on Cisco IP phones for internal and external communications. Unauthorized access to sensitive information could facilitate targeted espionage, social engineering, or lateral movement within networks. The impact is particularly significant for organizations handling sensitive personal data under GDPR, as unauthorized disclosure could lead to regulatory penalties and reputational damage. Additionally, compromised telephony devices could undermine trust in communication channels and disrupt business operations indirectly. Since Web Access is disabled by default, the risk is mitigated if organizations maintain secure configurations. However, if Web Access is enabled for management convenience without adequate network protections, the vulnerability could be exploited by attackers with network access, including insider threats or attackers who have breached perimeter defenses. The vulnerability does not affect device integrity or availability directly, so it is less likely to cause service outages but remains a serious confidentiality concern. Organizations in sectors such as finance, government, healthcare, and critical infrastructure are especially sensitive to such information exposure due to the nature of their communications and regulatory requirements.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-write-g3kcC5Df (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Sep 2025, 18:03 UTC

Technical details

References

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