CVE-2022-20837
CVE-2022-20837 is a high-severity vulnerability in Cisco Ios Xe with a CVSS 3.x base score of 8.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-754.
Key facts
- Severity: High (CVSS 3.x base score 8.6)
- EPSS exploit prediction: 1% (54th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-754
- Affected product: Cisco Ios Xe
- Published:
- Last modified:
Description
A vulnerability in the DNS application layer gateway (ALG) functionality that is used by Network Address Translation (NAT) in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. This vulnerability is due to a logic error that occurs when an affected device inspects certain TCP DNS packets. An attacker could exploit this vulnerability by sending crafted DNS packets through the affected device that is performing NAT for DNS packets. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition on the affected device. Note: This vulnerability can be exploited only by sending IPv4 TCP packets through an affected device. This vulnerability cannot be exploited by sending IPv6 traffic.
Frequently asked questions
- What is CVE-2022-20837?
- A vulnerability in the DNS application layer gateway (ALG) functionality that is used by Network Address Translation (NAT) in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. This vulnerability is due to a logic error that occurs when an affected device inspects certain TCP DNS packets. An attacker could exploit this vulnerability by sending crafted DNS packets through the affected device that is performing NAT for DNS packets. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition on the affected device. Note: This vulnerability can be exploited only by sending IPv4 TCP packets through an affected device. This vulnerability cannot be exploited by sending IPv6 traffic.
- How severe is CVE-2022-20837?
- CVE-2022-20837 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2022-20837 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2022-20837?
- CVE-2022-20837 affects Cisco Ios Xe. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2022-20837?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2022-20837 published?
- CVE-2022-20837 was published on 2022-10-10 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:o:cisco:ios_xe:-:*:*:*:*:*:*:*
More vulnerabilities in Cisco Ios Xe
- CVE-2025-20188 — Critical (CVSS 10.0): A vulnerability in the Out-of-Band Access Point (AP) Image Download, the Clean Air Spectral Recording, and the client…
- CVE-2023-20198 — Critical (CVSS 10.0): Cisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco…
- CVE-2021-34770 — Critical (CVSS 10.0): A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE…
- CVE-2019-12643 — Critical (CVSS 10.0): A vulnerability in the Cisco REST API virtual service container for Cisco IOS XE Software could allow an…
- CVE-2021-1619 — Critical (CVSS 9.8): A vulnerability in the authentication, authorization, and accounting (AAA) function of Cisco IOS XE Software could…
- CVE-2020-3227 — Critical (CVSS 9.8): A vulnerability in the authorization controls for the Cisco IOx application hosting infrastructure in Cisco IOS XE…
All CVEs affecting Cisco Ios Xe →
Other CWE-754 (Improper Check for Unusual or Exceptional Conditions) vulnerabilities
- CVE-2026-24054 — Critical (CVSS 10.0): Kata Containers is an open source project focusing on a standard implementation of lightweight Virtual Machines (VMs)…
- CVE-2021-0211 — Critical (CVSS 10.0): An improper check for unusual or exceptional conditions in Juniper Networks Junos OS and Junos OS Evolved Routing…
- CVE-2026-8091 — Critical (CVSS 9.8): Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150,…
- CVE-2024-52316 — Critical (CVSS 9.8): Unchecked Error Condition vulnerability in Apache Tomcat. If Tomcat is configured to use a custom Jakarta…
- CVE-2024-7826 — Critical (CVSS 9.8): Improper Check for Unusual or Exceptional Conditions vulnerability in Webroot SecureAnywhere - Web Shield on Windows,…
- CVE-2023-37303 — Critical (CVSS 9.8): An issue was discovered in the CheckUser extension for MediaWiki through 1.39.3. In certain situations, an attempt to…
Browse all CWE-754 (Improper Check for Unusual or Exceptional Conditions) vulnerabilities →