How severe is CVE-2020-26260?

CVE-2020-26260 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2020-26260 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-26260?

CVE-2020-26260 affects Bookstackapp Bookstack. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-26260?

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

When was CVE-2020-26260 published?

CVE-2020-26260 was published on 2020-12-09 and last updated on 2026-06-17.

CVE-2020-26260

CVE-2020-26260 is a medium-severity vulnerability in Bookstackapp Bookstack with a CVSS 3.x base score of 6.4. 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-74.

Key facts

Severity: Medium (CVSS 3.x base score 6.4)
CVSS v2: 5.5
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Bookstackapp Bookstack
Published: 2020-12-09
Last modified: 2026-06-17

Description

BookStack is a platform for storing and organising information and documentation. In BookStack before version 0.30.5, a user with permissions to edit a page could set certain image URL's to manipulate functionality in the exporting system, which would allow them to make server side requests and/or have access to a wider scope of files within the BookStack file storage locations. The issue was addressed in BookStack v0.30.5. As a workaround, page edit permissions could be limited to only those that are trusted until you can upgrade.

Frequently asked questions

What is CVE-2020-26260?: BookStack is a platform for storing and organising information and documentation. In BookStack before version 0.30.5, a user with permissions to edit a page could set certain image URL's to manipulate functionality in the exporting system, which would allow them to make server side requests and/or have access to a wider scope of files within the BookStack file storage locations. The issue was addressed in BookStack v0.30.5. As a workaround, page edit permissions could be limited to only those that are trusted until you can upgrade.
How severe is CVE-2020-26260?: CVE-2020-26260 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-26260 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-26260?: CVE-2020-26260 affects Bookstackapp Bookstack. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-26260?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-26260 published?: CVE-2020-26260 was published on 2020-12-09 and last updated on 2026-06-17.

References

Affected products (1)

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

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CVE-2021-4119 — Critical (CVSS 9.8): bookstack is vulnerable to Improper Access Control
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