How severe is CVE-2019-12706?

CVE-2019-12706 has a CVSS 3.x base score of 7.5, 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 high, and availability none.

Is CVE-2019-12706 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-12706?

CVE-2019-12706 affects Cisco Email Security Appliance Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-12706?

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-2019-12706 published?

CVE-2019-12706 was published on 2019-10-02 and last updated on 2026-06-17.

CVE-2019-12706

CVE-2019-12706 is a high-severity vulnerability in Cisco Email Security Appliance Firmware with a CVSS 3.x base score of 7.5. 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: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cisco Email Security Appliance Firmware
Published: 2019-10-02
Last modified: 2026-06-17

Description

A vulnerability in the Sender Policy Framework (SPF) functionality of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the configured user filters on an affected device. The vulnerability exists because the affected software insufficiently validates certain incoming SPF messages. An attacker could exploit this vulnerability by sending a custom SPF packet to an affected device. A successful exploit could allow the attacker to bypass the configured header filters, which could allow malicious content to pass through the device.

Frequently asked questions

What is CVE-2019-12706?: A vulnerability in the Sender Policy Framework (SPF) functionality of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the configured user filters on an affected device. The vulnerability exists because the affected software insufficiently validates certain incoming SPF messages. An attacker could exploit this vulnerability by sending a custom SPF packet to an affected device. A successful exploit could allow the attacker to bypass the configured header filters, which could allow malicious content to pass through the device.
How severe is CVE-2019-12706?: CVE-2019-12706 has a CVSS 3.x base score of 7.5, 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 high, and availability none.
Is CVE-2019-12706 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-12706?: CVE-2019-12706 affects Cisco Email Security Appliance Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-12706?: 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-2019-12706 published?: CVE-2019-12706 was published on 2019-10-02 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20191002-esa-bypass

Affected products (1)

cpe:2.3:o:cisco:email_security_appliance_firmware:*:*:*:*:*:*:*:*

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