How severe is CVE-2021-4119?

CVE-2021-4119 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-4119 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 27% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-4119?

CVE-2021-4119 affects Bookstackapp Bookstack. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-4119?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-4119 published?

CVE-2021-4119 was published on 2021-12-15 and last updated on 2026-06-17.

CVE-2021-4119

CVE-2021-4119 is a critical-severity vulnerability in Bookstackapp Bookstack with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 27% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-284.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 27% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Affected product: Bookstackapp Bookstack
Published: 2021-12-15
Last modified: 2026-06-17

Description

bookstack is vulnerable to Improper Access Control

Frequently asked questions

What is CVE-2021-4119?: bookstack is vulnerable to Improper Access Control
How severe is CVE-2021-4119?: CVE-2021-4119 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-4119 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 27% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-4119?: CVE-2021-4119 affects Bookstackapp Bookstack. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-4119?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-4119 published?: CVE-2021-4119 was published on 2021-12-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:bookstackapp:bookstack:*:*:*:*:*:*:*:*

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