VulnerabilityPublished 7 Jan 2026Updated 12 Feb 2026

CVE-2026-20027: Cisco Secure Firewall Threat Defense (FTD) Software · Information Exposure

Affects Cisco Secure Firewall Threat Defense (FTD) SoftwareSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 48% 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 7 Jan 2026
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
CiscoCisco Secure Firewall Threat Defense (FTD) Software	Affected 7.0.0 – 7.7.10.1 57 affected builds	Fixed in–
CiscoCisco UTD SNORT IPS Engine Software	Affected 3.17.0S – 17.18.2 88 affected builds	Fixed in–

AI-suggested

Organizations should prioritize applying official Cisco patches or updates addressing CVE-2026-20027 as soon as they become available. In the interim, network administrators should consider limiting or blocking unnecessary DCE/RPC traffic at network boundaries or within segmented environments to reduce exposure. Deploying strict access controls and network segmentation can minimize the attack surface by restricting which systems can send DCE/RPC requests inspected by Cisco FTD devices. Monitoring network traffic for unusual spikes or patterns in DCE/RPC requests can help detect attempted exploitation. Additionally, reviewing and hardening Snort 3 detection engine configurations to minimize exposure to malformed packets may reduce risk. Organizations should also ensure comprehensive logging and alerting are enabled on Cisco FTD devices to facilitate rapid incident response. Coordination with Cisco support and threat intelligence teams can provide timely updates and guidance. Finally, conducting internal audits to identify all affected Cisco FTD versions in use will help prioritize remediation efforts.

Description

Multiple Cisco products are affected by a vulnerability in the processing of DCE/RPC requests that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to leak sensitive information or to restart, resulting in an interruption of packet inspection. This vulnerability is due to an error in buffer handling logic when processing DCE/RPC requests, which can result in a buffer out-of-bounds read. An attacker could exploit this vulnerability by sending a large number of DCE/RPC requests through an established connection that is inspected by Snort 3. A successful exploit could allow the attacker to obtain sensitive information in the Snort 3 data stream.

Impact

For European organizations, the vulnerability poses a risk of sensitive information leakage from network traffic inspected by Cisco FTD devices, potentially exposing internal network details or security telemetry. The ability to cause Snort 3 engine restarts can disrupt network traffic inspection temporarily, reducing visibility and increasing the risk of undetected malicious activity during downtime. Organizations in sectors with stringent data protection requirements, such as finance, healthcare, and critical infrastructure, may face compliance and operational risks if sensitive data is exposed. The unauthenticated, remote nature of the exploit increases the threat surface, especially for organizations exposing DCE/RPC traffic or using Cisco FTD in environments with high volumes of such traffic. The impact on confidentiality is moderate, but the potential for service interruption and information leakage could facilitate further attacks or reconnaissance by threat actors. Given Cisco's significant market share in European enterprise and government networks, the vulnerability could affect a wide range of organizations, from SMEs to large enterprises and public sector entities.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-dcerpc-vulns-J9HNF4tH (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Feb 2026, 06:44 UTC

Technical details

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