How severe is CVE-2020-13998?

CVE-2020-13998 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2020-13998 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-13998?

CVE-2020-13998 affects Citrix Xenapp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-13998?

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

When was CVE-2020-13998 published?

CVE-2020-13998 was published on 2020-06-11 and last updated on 2026-06-17.

CVE-2020-13998

CVE-2020-13998 is a medium-severity vulnerability in Citrix Xenapp with a CVSS 3.x base score of 5.3. 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-203.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-203
Affected product: Citrix Xenapp
Published: 2020-06-11
Last modified: 2026-06-17

Description

Citrix XenApp 6.5, when 2FA is enabled, allows a remote unauthenticated attacker to ascertain whether a user exists on the server, because the 2FA error page only occurs after a valid username is entered. NOTE: This vulnerability only affects products that are no longer supported by the maintainer

Frequently asked questions

What is CVE-2020-13998?: Citrix XenApp 6.5, when 2FA is enabled, allows a remote unauthenticated attacker to ascertain whether a user exists on the server, because the 2FA error page only occurs after a valid username is entered. NOTE: This vulnerability only affects products that are no longer supported by the maintainer
How severe is CVE-2020-13998?: CVE-2020-13998 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2020-13998 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-13998?: CVE-2020-13998 affects Citrix Xenapp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-13998?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-13998 published?: CVE-2020-13998 was published on 2020-06-11 and last updated on 2026-06-17.

References

https://gist.github.com/kampji/11e259d68ad98a6f0f898132f1961a96

Affected products (1)

cpe:2.3:a:citrix:xenapp:6.5.0.0:*:*:*:*:*:*:*

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