How severe is CVE-2019-1951?

CVE-2019-1951 has a CVSS 3.x base score of 5.8, 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 low, and availability none.

Is CVE-2019-1951 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-1951?

CVE-2019-1951 affects Cisco Sd-wan Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-1951?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2019-1951 published?

CVE-2019-1951 was published on 2019-08-08 and last updated on 2026-06-17.

CVE-2019-1951

CVE-2019-1951 is a medium-severity vulnerability in Cisco Sd-wan Firmware with a CVSS 3.x base score of 5.8. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
CVSS v2: 5.0
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cisco Sd-wan Firmware
Published: 2019-08-08
Last modified: 2026-06-17

Description

A vulnerability in the packet filtering features of Cisco SD-WAN Solution could allow an unauthenticated, remote attacker to bypass L3 and L4 traffic filters. The vulnerability is due to improper traffic filtering conditions on an affected device. An attacker could exploit this vulnerability by crafting a malicious TCP packet with specific characteristics and sending it to a target device. A successful exploit could allow the attacker to bypass the L3 and L4 traffic filters and inject an arbitrary packet in the network.

Frequently asked questions

What is CVE-2019-1951?: A vulnerability in the packet filtering features of Cisco SD-WAN Solution could allow an unauthenticated, remote attacker to bypass L3 and L4 traffic filters. The vulnerability is due to improper traffic filtering conditions on an affected device. An attacker could exploit this vulnerability by crafting a malicious TCP packet with specific characteristics and sending it to a target device. A successful exploit could allow the attacker to bypass the L3 and L4 traffic filters and inject an arbitrary packet in the network.
How severe is CVE-2019-1951?: CVE-2019-1951 has a CVSS 3.x base score of 5.8, 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 low, and availability none.
Is CVE-2019-1951 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-1951?: CVE-2019-1951 affects Cisco Sd-wan Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-1951?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-1951 published?: CVE-2019-1951 was published on 2019-08-08 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190807-sd-wan-bypass

Affected products (1)

cpe:2.3:o:cisco:sd-wan_firmware:*:*:*:*:*:*:*:*

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