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.

According to its self-reported version, Cisco IOS-XE Software is affected by the following vulnerabilities:

  - 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 use-after-free 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 unexpectedly restart the Snort 3     Detection Engine, which could cause a denial of service (DoS). (CVE-2026-20026)

  - 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. (CVE-2026-20027)

Please see the included Cisco BIDs and Cisco Security Advisory for more information.

According to its self-reported version, the Cisco Meraki device is affected by the following vulnerabilities.:

  - 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 use-after-free 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 unexpectedly restart the Snort 3     Detection Engine, which could cause a denial of service (DoS). (CVE-2026-20026)

  - 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. (CVE-2026-20027)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

According to its self-reported version, Cisco Secure Firewall Threat Defense (FTD) Software is affected by the following vulnerabilities:

  - 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 use-after-free 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 unexpectedly restart the Snort 3     Detection Engine, which could cause a denial of service (DoS). (CVE-2026-20026)

  - 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. (CVE-2026-20027)

Please see the included Cisco BIDs and Cisco Security Advisory for more information.

ID	Name	Product	Family	Severity
290255	Cisco IOS XE Software Unified Threat Defense Snort Intrusion Prevention System Engine Multiple Vulnerabilities (cisco-sa-snort3-dcerpc-vulns-J9HNF4tH)	Nessus	CISCO	medium
290254	Cisco Meraki Multiple Vulnerabilities (cisco-sa-snort3-dcerpc-vulns-J9HNF4tH)	Nessus	CISCO	medium
290253	Cisco Firepower Threat Defense (FTD) Software Multiple Vulnerabilities (cisco-sa-snort3-dcerpc-vulns-J9HNF4tH)	Nessus	CISCO	medium

Detections

Analytics

CVE-2026-20027

medium

Tenable Plugins

medium

medium

medium