CVE-2021-1394
CVE-2021-1394 is a medium-severity vulnerability in Cisco Ios Xe with a CVSS 3.x base score of 5.3. 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-399.
Key facts
- Severity: Medium (CVSS 3.x base score 5.3)
- CVSS v2: 4.3
- EPSS exploit prediction: 1% (66th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-399
- Affected product: Cisco Ios Xe
- Published:
- Last modified:
Description
A vulnerability in the ingress traffic manager of Cisco IOS XE Software for Cisco Network Convergence System (NCS) 520 Routers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition in the web management interface of an affected device. This vulnerability is due to incorrect processing of certain IPv4 TCP traffic that is destined to an affected device. An attacker could exploit this vulnerability by sending a large number of crafted TCP packets to the affected device. A successful exploit could allow the attacker to cause the web management interface to become unavailable, resulting in a DoS condition. Note: This vulnerability does not impact traffic that is going through the device or going to the Management Ethernet interface of the device.
Frequently asked questions
- What is CVE-2021-1394?
- A vulnerability in the ingress traffic manager of Cisco IOS XE Software for Cisco Network Convergence System (NCS) 520 Routers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition in the web management interface of an affected device. This vulnerability is due to incorrect processing of certain IPv4 TCP traffic that is destined to an affected device. An attacker could exploit this vulnerability by sending a large number of crafted TCP packets to the affected device. A successful exploit could allow the attacker to cause the web management interface to become unavailable, resulting in a DoS condition. Note: This vulnerability does not impact traffic that is going through the device or going to the Management Ethernet interface of the device.
- How severe is CVE-2021-1394?
- CVE-2021-1394 has a CVSS 3.x base score of 5.3, rated medium 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 low.
- Is CVE-2021-1394 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-1394?
- CVE-2021-1394 primarily affects Cisco Ios Xe. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-1394?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2021-1394 published?
- CVE-2021-1394 was published on 2021-03-24 and last updated on 2026-06-17.
References
Affected products (10)
- cpe:2.3:o:cisco:ios_xe:16.10.1:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:16.10.1a:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:16.10.1b:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:16.10.1c:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:16.10.1d:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:16.10.1e:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:16.10.1f:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:16.10.1g:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:16.10.1s:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:ios_xe:17.2.1v:*:*:*:*:*:*:*
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