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% (72nd 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% (72nd 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% (72nd 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:*:*:*:*:*:*:*

More vulnerabilities in Cisco Web Security Appliance

CVE-2023-20032 — Critical (CVSS 9.8): On Feb 15, 2023, the following vulnerability in the ClamAV scanning library was disclosed: A vulnerability in the…
CVE-2015-6298 — Critical (CVSS 9.0): The admin web interface in Cisco AsyncOS 8.x before 8.0.8-113, 8.1.x and 8.5.x before 8.5.3-051, 8.6.x and 8.7.x before…
CVE-2019-15956 — High (CVSS 8.8): A vulnerability in the web management interface of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA) could…
CVE-2019-1886 — High (CVSS 8.6): A vulnerability in the HTTPS decryption feature of Cisco Web Security Appliance (WSA) could allow an unauthenticated,…
CVE-2018-0410 — High (CVSS 8.6): A vulnerability in the web proxy functionality of Cisco AsyncOS Software for Cisco Web Security Appliances could allow…
CVE-2019-1816 — High (CVSS 7.8): A vulnerability in the log subscription subsystem of the Cisco Web Security Appliance (WSA) could allow an…

All CVEs affecting Cisco Web Security Appliance →

Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities

CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…
CVE-2025-1866 — Critical (CVSS 10.0): Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in warmcat libwebsockets allows…
CVE-2022-27625 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2022-27624 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.

Browse all CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities →