5.3

CVE-2021-26085: Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability

KEVRansomware
Analyzed
Published 03-08-2021Last modified 21-10-2025

Vulnerability summary

CVE-2021-26085 is a medium (CVSS 5.3) Direct Request vulnerability in Atlassian Confluence Server. It is known to be exploited: CISA lists it, first on 28-03-2022. It has been used in ransomware campaigns. EPSS estimates a 99.94% chance of exploitation in the next 30 days, higher than 99.9% of scored vulnerabilities. 2 public exploits are recorded.

Priority
Act nowransomware

Known ransomware use (CISA, 28-03-2022)

Source freshness unavailable

How is this decided?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
99.94%
0%100%
Critical · 0.00 pp in 30 days
KEVExploited in the wildCritical · listed in 1 catalog
RansomwareKnown useFlagged by CISA
Public exploits2reference, exploit-database

Timeline

  1. 03-08-2021
    PublishedVulnerability first disclosed.
  2. 28-03-2022
    Added to CISA KEVExploitedAtlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability
  3. 18-04-2022
    CISA remediation dueDeadline passedApply updates per vendor instructions.
  4. 21-10-2025
    Last modifiedVulnerability information updated.

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 metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

99.94%

Chance of exploitation in the next 30 days

Percentile

100%

Versus all other CVEs

30-day change

No change 0.00 pp

From 99.94% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
28-03-2022
Federal due date
18-04-2022
Ransomware
ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

CISA required action

Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2021-26085

Public exploits

2 found
  • referenceUnverified

    Exploit Reference (packetstormsecurity.com)

    Maturity: unknown

  • exploit-databasejavaUnverified

    Atlassian Confluence 7.12.2 - Pre-Authorization Arbitrary File Read

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Atlassian2 products
  • confluence_data_center≥ unspecified, < 7.4.10 | ≥ 7.5.0, < unspecified | ≥ unspecified, < 7.12.3 | < 7.4.10 | ≥ 7.5.0, < 7.12.3
  • confluence_server≥ unspecified, < 7.4.10 | ≥ 7.5.0, < unspecified | ≥ unspecified, < 7.12.3 | < 7.4.10 | ≥ 7.5.0, < 7.12.3

1 vendor · 2 products

References

3 links