CVE-2021-34787
MEDIUMDescription
A vulnerability in the identity-based firewall (IDFW) rule processing feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass security protections. This vulnerability is due to improper handling of network requests by affected devices configured to use object group search. An attacker could exploit this vulnerability by sending a specially crafted network request to an affected device. A successful exploit could allow the attacker to bypass access control list (ACL) rules on the device, bypass security protections, and send network traffic to unauthorized hosts.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Exploit Intelligence
Moderate risk: more likely to be exploited than 60% of all known CVEs.
References
Related Vulnerabilities
Other CWE-183 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-25696 | High | 7.5 | 2.6% | - | Fix |
| CVE-2026-21915 | Medium | 6.7 | 2.2% | - | Fix |
| CVE-2020-1694 | Medium | 4.9 | 1.6% | - | Fix |
| CVE-2024-1654 | High | 7.2 | 1.3% | - | Fix |
| CVE-2023-4399 | Medium | 6.6 | 1.1% | - | Fix |
| CVE-2021-40128 | Medium | 5.3 | 1.0% | - | - |
Common questions
How do I fix CVE-2021-34787?
Published advisories record a fix for 3 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2021-34787 being actively exploited?
Not that we know of. CVE-2021-34787 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.0% is the estimated probability that it will be exploited in the next 30 days. That is higher than 60% of all scored CVEs.
How severe is CVE-2021-34787?
CVE-2021-34787 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-34787 affect?
Published advisories record a fix for adaptive security appliance (NVD), adaptive security appliance software (NVD), firepower threat defense (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.