How severe is CVE-2021-27564?

CVE-2021-27564 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-27564 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27564?

CVE-2021-27564 affects Appspace. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27564?

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

When was CVE-2021-27564 published?

CVE-2021-27564 was published on 2021-02-22 and last updated on 2026-06-17.

CVE-2021-27564

CVE-2021-27564 is a medium-severity vulnerability in Appspace with a CVSS 3.x base score of 5.4. 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

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Appspace
Published: 2021-02-22
Last modified: 2026-06-17

Description

A stored XSS issue exists in Appspace 6.2.4. After a user is authenticated and enters an XSS payload under the groups section of the network tab, it is stored as the group name. Whenever another member visits that group, this payload executes.

Frequently asked questions

What is CVE-2021-27564?: A stored XSS issue exists in Appspace 6.2.4. After a user is authenticated and enters an XSS payload under the groups section of the network tab, it is stored as the group name. Whenever another member visits that group, this payload executes.
How severe is CVE-2021-27564?: CVE-2021-27564 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-27564 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27564?: CVE-2021-27564 affects Appspace. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27564?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-27564 published?: CVE-2021-27564 was published on 2021-02-22 and last updated on 2026-06-17.

References

https://github.com/viperbluff/Appspace-Ver-6.2.4-Stored-Xss

Affected products (1)

cpe:2.3:a:appspace:appspace:6.2.4:*:*:*:*:*:*:*

More vulnerabilities in Appspace

CVE-2021-27670 — Critical (CVSS 9.8): Appspace 6.2.4 allows SSRF via the api/v1/core/proxy/jsonprequest url parameter.
CVE-2021-27990 — High (CVSS 7.5): Appspace 6.2.4 is vulnerable to a broken authentication mechanism where pages such as /medianet/mail.aspx can be called…
CVE-2021-27704 — Medium (CVSS 6.5): Appspace 6.2.4 is affected by Incorrect Access Control via the Appspace Web Portal password reset page.
CVE-2021-27989 — Medium (CVSS 5.4): Appspace 6.2.4 is vulnerable to stored cross-site scripting (XSS) in multiple parameters within…

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