CVE-2021-1495
MediumCVSS 5.8Exploitation Probability (EPSS)
High risk75th percentile - higher than 75% of all known CVEs
Summary
A vulnerability in the Snort detection engine of multiple Cisco products could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. The issue is due to incorrect handling of specific HTTP header parameters. An attacker could exploit this by sending crafted HTTP packets through an affected device, bypassing the policy and delivering a malicious payload.
Risk Assessment
The risk is that malicious software could be delivered into the network despite configured security policies, potentially leading to system compromise.
Recommendation
It is recommended to upgrade Cisco software to a patched version for Snort and review file policy configurations.
Other vulnerabilities in Cisco Snort
See all- CVE-2026-20057Medium
A vulnerability in the VBA feature of the Snort 3 engine in multiple Cisco products allows an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash. This is due to lack of proper error checking when decompressing VBA data. A successful exploit could cause the engine to unexpectedly restart, leading to a DoS condition.
- CVE-2026-20054Medium
A vulnerability in the VBA feature of the Snort 3 engine in multiple Cisco products allows an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash. This is due to improper error checking when decompressing VBA data. A successful exploit could cause the engine to enter an infinite loop, leading to a DoS condition.
- CVE-2026-20053Medium
A vulnerability in the VBA feature of the Snort 3 engine in multiple Cisco products allows an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash. This is due to improper range checking when decompressing user-controlled VBA data. A successful exploit could cause an overflow of heap data, leading to a DoS condition.
- CVE-2026-20027Medium
Multiple Cisco products are affected by an out-of-bounds read in buffer handling when processing DCE/RPC requests in the Snort 3 Detection Engine. An unauthenticated remote attacker could send many requests over an established connection to obtain sensitive information from the Snort 3 data stream.
- CVE-2026-20026Medium
Multiple Cisco products are affected by a vulnerability in DCE/RPC request processing that can cause a buffer use-after-free read. An unauthenticated remote attacker could send many DCE/RPC requests over an established connection to leak sensitive information or restart the Snort 3 Detection Engine.
- CVE-2022-20943Medium
Multiple vulnerabilities in the SMB2 processor of the Snort detection engine on multiple Cisco products could allow an unauthenticated, remote attacker to bypass configured policies or cause a denial of service (DoS) condition. This is due to improper management of system resources when processing SMB2 traffic. An attacker could send a high rate of SMB2 packets to trigger a reload of the Snort process. With preserve-connection enabled (default), policy bypass and malicious payload delivery are also possible.
Original NVD description (English source)
Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. The vulnerability is due to incorrect handling of specific HTTP header parameters. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured file policy for HTTP packets and deliver a malicious payload.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS