How severe is CVE-2017-3870?

CVE-2017-3870 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-2017-3870 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-3870?

CVE-2017-3870 primarily affects Cisco Web Security Appliance. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-3870?

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

When was CVE-2017-3870 published?

CVE-2017-3870 was published on 2017-03-17 and last updated on 2026-06-17.

CVE-2017-3870

CVE-2017-3870 is a medium-severity vulnerability in Cisco Web Security Appliance 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-119.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
CVSS v2: 5.0
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Cisco Web Security Appliance
Published: 2017-03-17
Last modified: 2026-06-17

Description

A vulnerability in the URL filtering feature of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass a configured URL filter rule. Affected Products: This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA), both virtual and hardware appliances, that are configured with URL filters for email scanning. More Information: CSCvc69700. Known Affected Releases: 8.5.3-069 9.1.1-074 9.1.2-010.

Frequently asked questions

What is CVE-2017-3870?: A vulnerability in the URL filtering feature of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass a configured URL filter rule. Affected Products: This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA), both virtual and hardware appliances, that are configured with URL filters for email scanning. More Information: CSCvc69700. Known Affected Releases: 8.5.3-069 9.1.1-074 9.1.2-010.
How severe is CVE-2017-3870?: CVE-2017-3870 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-2017-3870 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-3870?: CVE-2017-3870 primarily affects Cisco Web Security Appliance. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-3870?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2017-3870 published?: CVE-2017-3870 was published on 2017-03-17 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:cisco:web_security_appliance:8.5.3-069:*:*:*:*:*:*:*
cpe:2.3:a:cisco:web_security_appliance:9.1.1-074:*:*:*:*:*:*:*
cpe:2.3:a:cisco:web_security_appliance:9.1.2-010:*:*:*:*:*:*:*

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