VulnerabilityPublished 20 Aug 2025

CVE-2025-20345: Cisco Duo Authentication Proxy · Information Exposure

Affects Cisco Duo Authentication ProxySource CVE Database V5

Not known to be exploited · CVSS 4.9 Medium.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score

4.9Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Unchanged
Confidentiality: High
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: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
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 20 Aug 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
Cisco Cisco Duo Authentication Proxy	Affected 2.4.2 – 6.0.0 68 affected builds	Fixed in–

AI-suggested

Immediate review and restriction of access to system logs containing sensitive information, ensuring only authorized personnel with a strict need-to-know can access these logs.
Implement robust monitoring and alerting on access to authentication proxy logs to detect unusual or unauthorized access patterns.
Apply the latest Cisco Duo Authentication Proxy updates as soon as Cisco releases patches addressing this vulnerability; monitor Cisco security advisories closely.
If patches are not yet available, consider disabling debug logging or configuring logging to minimize sensitive data exposure, if feasible within operational constraints.
Enforce strict privilege management and credential hygiene to reduce the risk of high-privileged account compromise, including multi-factor authentication for administrative access.
Conduct regular audits of log files and access controls to ensure compliance with security policies.
Employ network segmentation to limit access to authentication proxy systems and their logs, reducing the attack surface.
Educate administrators about the risks of sensitive data exposure in logs and best practices for secure log management.

Description

A vulnerability in the debug logging function of Cisco Duo Authentication Proxy could allow an authenticated, high-privileged, remote attacker to view sensitive information in a system log file. This vulnerability is due to insufficient masking of sensitive information before it is written to system log files. An attacker could exploit this vulnerability by accessing logs on an affected system. A successful exploit could allow the attacker to view sensitive information that should be restricted. 

Impact

For European organizations, the impact of this vulnerability can be significant, especially for those relying on Cisco Duo Authentication Proxy for securing access to critical systems via MFA. Exposure of sensitive information in logs can lead to credential leakage or disclosure of internal authentication mechanisms, undermining the security posture and potentially enabling lateral movement or privilege escalation within networks. Organizations in sectors with stringent data protection requirements, such as finance, healthcare, and government, may face regulatory and compliance risks if sensitive data is exposed. Additionally, the breach of MFA-related data could erode trust in authentication systems and increase the risk of account compromise. Since the vulnerability requires high-privileged authenticated access, insider threats or attackers who have already gained elevated credentials pose the greatest risk. The widespread use of Cisco Duo in European enterprises and public sector entities means that many organizations could be affected if they have not updated or mitigated this issue. The lack of known exploits in the wild reduces immediate risk but does not eliminate the potential for targeted attacks or future exploitation.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 20 Aug 2025, 16:48 UTC

Technical details

References

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