Vulnerability feed

Multiple Cisco products are affected by a vulnerability in the memory management implementation of Snort 3 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 Snort 3 processes files, which could cause unreleased memory. An attacker could exploit this vulnerability by sending a large number of files to be processed. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.

Multiple Cisco products are affected by a vulnerability in the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause the detection engine to unexpectedly restart, resulting in a denial of service (DoS) condition.

The vulnerability is due to a flaw in logic handling when General Packet Radio Service (GPRS) Tunneling Protocol (GTP) extension headers are processed within the codec. An attacker could exploit this vulnerability by sending a crafted, fragmented UDP datagram that contains these headers to the Snort 3 Detection Engine of an affected device. A successful exploit could allow the attacker to cause the detection engine to enter an infinite loop, resulting in a DoS condition.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-20356 are related to issues concerning uncontrolled resource consumption that are grouped under the Common Weakness Enumeration (CWE) Base CWE-400.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-20291 are related to issues concerning improper privilege management that are grouped under the Common Weakness Enumeration (CWE) Base CWE-269.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-20236 are related to issues concerning incorrect calculation that are grouped under the Common Weakness Enumeration (CWE) Base CWE-682.

Multiple Cisco products are affected by a vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause an unexpected restart of the Snort 3 Detection Engine.

This vulnerability is due to improper handling of nested GRE traffic. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 Detection Engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. For more information, see the section of this advisory. The Snort 3 Detection Engine will restart automatically. No manual intervention is required.

A vulnerability in the Snort 3 Visual Basic for Applications (VBA) Decompression Engine of multiple Cisco products could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.  

This vulnerability is due to improper range checking when Snort 3 decompresses VBA data, which is user controlled. An attacker could exploit this vulnerability by sending crafted VBA data to the Snort 3 Detection Engine of a targeted device. A successful exploit could allow the attacker to cause an overflow of stack data, which could result in a DoS condition.

Multiple Cisco products are affected by a vulnerability in the Snort 3 Teredo 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 Snort 3 parses Teredo packets. An attacker could exploit this vulnerability by sending a crafted Teredo packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.

Multiple Cisco products are affected by a vulnerability in the Snort 3 Generic Routing Encapsulation (GRE) 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 Snort 3 parses GRE packets. An attacker could exploit this vulnerability by sending a crafted GRE packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-20043 are related to issues concerning out-of-bounds writes that are grouped under the Common Weakness Enumeration (CWE) Base CWE-787.

Multiple Cisco products are affected by a vulnerability in the Snort 3 NetFlow 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 Snort 3 parses UDP Netflow Protocol packets. An attacker could exploit this vulnerability by sending a single crafted Netflow packet through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.

Multiple Cisco products are affected by a vulnerability in the Snort 3 SMTP MIME Decoder that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart.

This vulnerability is due to a lack of error checking when the MIME fields of the SMTP header are parsed. An attacker could exploit this vulnerability by sending crafted SMTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.