Secuno
ENNL
Book demo

CVE-2021-26085

Atlassian Confluence Server Pre-Authorization Arbitrary File Read

5.3 MEDIUMActively exploited (CISA KEV)Used in ransomwarePublic exploitEPSS 99.9%
  1. Published2 Aug 2021
  2. Added to CISA KEV28 Mar 2022
  3. Remediation due18 Apr 2022
Actively exploited (CISA KEV)

Affected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a pre-authorization arbitrary file read vulnerability in the /s/ endpoint.

Added to KEV: 28 Mar 2022Federal remediation due: 18 Apr 2022Used in ransomware

Description

Affected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a Pre-Authorization Arbitrary File Read vulnerability in the /s/ endpoint. The affected versions are before version 7.4.10, and from version 7.5.0 before 7.12.3.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityLow
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected products

Atlassian Confluence Data Center≥ 7.5.0 < 7.12.3 · < 7.4.10
Atlassian Confluence Server≥ 7.5.0 < 7.12.3 · < 7.4.10

Remediation

Fixed in
Atlassian Confluence Data Center≥ 7.12.3
Atlassian Confluence Server≥ 7.12.3

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-877449.1
A flaw was found in Quarkus REST Data Panache. This vulnerability allows…
CVE-2026-802758.8
Comelit Multi-User Gateway for VIP System (model 1456B) firmware versions 2.9.1 and…
CVE-2026-422978.3
Argo Workflows is an open source container-native workflow engine for orchestrating…
CVE-2026-350298.8
LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format.…
CVE-2026-227329.1
When applications specify HTTP response headers for servlet applications using Spring…
CVE-2025-520249.4
A vulnerability exists in the Aptsys POS Platform Web Services module thru 2025-05-28,…

Frequently asked

Is CVE-2021-26085 being actively exploited?

Yes. CVE-2021-26085 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 28 Mar 2022. It has been used in ransomware campaigns.

How severe is CVE-2021-26085?

CVE-2021-26085 has a CVSS 3.1 base score of 5.3, rated medium. EPSS estimates a 99.9% probability of exploitation.

Which products are affected by CVE-2021-26085?

Affected products include Atlassian Confluence Data Center, Atlassian Confluence Server.

How do I fix CVE-2021-26085?

Upgrade affected software to a fixed version, for example Atlassian Confluence Data Center 7.12.3, Atlassian Confluence Server 7.12.3 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-26085 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.