CVE-2020-13959

CVE-2020-13959 is a medium-severity vulnerability in Apache Velocity Tools with a CVSS 3.x base score of 6.1. 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-79.

Key facts

Description

The default error page for VelocityView in Apache Velocity Tools prior to 3.1 reflects back the vm file that was entered as part of the URL. An attacker can set an XSS payload file as this vm file in the URL which results in this payload being executed. XSS vulnerabilities allow attackers to execute arbitrary JavaScript in the context of the attacked website and the attacked user. This can be abused to steal session cookies, perform requests in the name of the victim or for phishing attacks.

Frequently asked questions

What is CVE-2020-13959?
The default error page for VelocityView in Apache Velocity Tools prior to 3.1 reflects back the vm file that was entered as part of the URL. An attacker can set an XSS payload file as this vm file in the URL which results in this payload being executed. XSS vulnerabilities allow attackers to execute arbitrary JavaScript in the context of the attacked website and the attacked user. This can be abused to steal session cookies, perform requests in the name of the victim or for phishing attacks.
How severe is CVE-2020-13959?
CVE-2020-13959 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-13959 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-13959?
CVE-2020-13959 primarily affects Apache Velocity Tools. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-13959?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-13959 published?
CVE-2020-13959 was published on 2021-03-10 and last updated on 2026-06-17.

References

Affected products (2)

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