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CVE-2021-40116

HIGHCVSS 7.5/10EPSS 1.35%

Last modified

CVE-2021-40116 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Multiple Cisco products are affected by a vulnerability in Snort rules that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.The vulnerability is due to improper handling of the Block with Reset or Interactive Block with Reset actions if a rule is configured without proper constraints. An attacker could exploit this vulnerability by sending a crafted IP packet to the affected device. EPSS estimates a 1.35% chance of exploitation in the next 30 days.

Description

Multiple Cisco products are affected by a vulnerability in Snort rules that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.The vulnerability is due to improper handling of the Block with Reset or Interactive Block with Reset actions if a rule is configured without proper constraints. An attacker could exploit this vulnerability by sending a crafted IP packet to the affected device. A successful exploit could allow the attacker to cause through traffic to be dropped. Note: Only products with Snort3 configured and either a rule with Block with Reset or Interactive Block with Reset actions configured are vulnerable. Products configured with Snort2 are not vulnerable.

Metrics

CVSS 3.1
7.5/10

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

EPSS Probability
1.35%

67.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
CiscoFirepower Threat Defense>= 6.4.0, < 6.4.0.13
CiscoFirepower Threat Defense>= 6.6.0, < 6.6.5.1
CiscoFirepower Threat Defense>= 6.7.0, < 6.7.0.3
CiscoFirepower Threat Defense>= 7.0.0, < 7.0.1
CiscoSecure Firewall Management Center3.1.0.1
CiscoSnort>= 3.0.0.0, < 3.1.0.100

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-40116?
Multiple Cisco products are affected by a vulnerability in Snort rules that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.The vulnerability is due to improper handling of the Block with Reset or Interactive Block with Reset actions if a rule is configured without proper constraints. An attacker could exploit this vulnerability by sending a crafted IP packet to the affected device. A successful exploit could allow the attacker to cause through traffic to be dropped. Note: Only products with Snort3 configured and either a rule with Block with Reset or Interactive Block with Reset actions configured are vulnerable. Products configured with Snort2 are not vulnerable.
How severe is CVE-2021-40116?
CVE-2021-40116 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.35% probability of exploitation in the next 30 days.
How do I fix CVE-2021-40116?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-40116?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST