VulnerabilityPublished 4 Mar 2026

CVE-2026-20067: Cisco Cyber Vision · Out-of-bounds Write

Affects Cisco Cyber VisionSource CVE Database V5

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Not known to be exploited · CVSS 5.8 Medium · patch available : update Cisco Cyber Vision when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

5.8Medium

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.
Patch: Available

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

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

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: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
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 impacted component 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 impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 Cyber Vision	Affected >=4.2.0 <4.3.0 – 5.3.2 54 affected builds	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 17.2.1r – 17.18.2 71 affected builds	Fixed in–

AI-suggested

1. 2. Until patches are deployed, implement network-level filtering to block or limit suspicious HTTP traffic containing malformed Multicast DNS fields, potentially using upstream firewalls or intrusion prevention systems. 3. Monitor network traffic for unusual patterns or repeated HTTP packets that could indicate attempts to exploit this vulnerability. 4. Consider deploying redundant or failover detection engines to maintain continuous packet inspection if one instance restarts unexpectedly. 5. Review and harden configurations of Cisco Cyber Vision deployments to minimize exposure to untrusted networks, such as restricting management interfaces and detection engine access to trusted segments. 6. Engage in proactive threat hunting and incident response readiness to quickly detect and respond to any signs of exploitation attempts. 7. Coordinate with Cisco support and subscribe to security advisories to stay informed about patches, workarounds, and emerging threat intelligence related to this vulnerability. 8. Conduct regular security assessments and penetration testing focused on network monitoring components to identify and remediate similar weaknesses.

Description

Multiple Cisco products are affected by a vulnerability in the Snort 3 detection engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.  This vulnerability is due to incomplete error checking when parsing the Multicast DNS fields of the HTTP header. An attacker could exploit this vulnerability by sending crafted HTTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine unexpectedly restarts.

Impact

The primary impact of CVE-2026-20067 is a denial-of-service condition on the Snort 3 Detection Engine within Cisco Cyber Vision, which disrupts packet inspection and network traffic analysis. This interruption can create blind spots in network security monitoring, allowing attackers to evade detection and potentially carry out further attacks undetected. For organizations relying on Cisco Cyber Vision for industrial control systems, critical infrastructure, or enterprise network security, this vulnerability could degrade situational awareness and incident response capabilities. Although the vulnerability does not directly compromise data confidentiality or integrity, the loss of availability of the detection engine can indirectly increase risk by reducing the effectiveness of intrusion detection and prevention systems. The ease of exploitation without authentication and user interaction means attackers can remotely trigger the DoS condition, potentially targeting multiple systems simultaneously. This could be leveraged as part of a broader attack strategy to weaken defenses before launching more damaging exploits. The widespread use of Cisco Cyber Vision in sectors such as manufacturing, energy, utilities, and large enterprises means the impact could be significant in environments where continuous network monitoring is critical for operational safety and compliance.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-multi-dos-XFWkWSwz (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Mar 2026, 20:18 UTC

Technical details

References

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