How severe is CVE-2021-3509?

CVE-2021-3509 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-2021-3509 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-2021-3509?

CVE-2021-3509 affects Redhat Ceph Storage. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3509?

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

When was CVE-2021-3509 published?

CVE-2021-3509 was published on 2021-05-27 and last updated on 2026-06-17.

CVE-2021-3509

CVE-2021-3509 is a medium-severity vulnerability in Redhat Ceph Storage 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

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Redhat Ceph Storage
Published: 2021-05-27
Last modified: 2026-06-17

Description

A flaw was found in Red Hat Ceph Storage 4, in the Dashboard component. In response to CVE-2020-27839, the JWT token was moved from localStorage to an httpOnly cookie. However, token cookies are used in the body of the HTTP response for the documentation, which again makes it available to XSS.The greatest threat to the system is for confidentiality, integrity, and availability.

Frequently asked questions

What is CVE-2021-3509?: A flaw was found in Red Hat Ceph Storage 4, in the Dashboard component. In response to CVE-2020-27839, the JWT token was moved from localStorage to an httpOnly cookie. However, token cookies are used in the body of the HTTP response for the documentation, which again makes it available to XSS.The greatest threat to the system is for confidentiality, integrity, and availability.
How severe is CVE-2021-3509?: CVE-2021-3509 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-2021-3509 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-2021-3509?: CVE-2021-3509 affects Redhat Ceph Storage. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3509?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-3509 published?: CVE-2021-3509 was published on 2021-05-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:redhat:ceph_storage:4.0:*:*:*:*:*:*:*

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