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PatchSiren cyber security CVE debrief

CVE-2021-26085 Atlassian CVE debrief

CVE-2021-26085 is a pre-authorization arbitrary file read issue in Atlassian Confluence Server. CISA lists it in the Known Exploited Vulnerabilities catalog, with known ransomware campaign use marked as known. For defenders, the key signal is that affected Confluence Server instances should be patched promptly and validated for exposure.

Vendor
Atlassian
Product
Confluence Server
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2022-03-28
Original CVE updated
2022-03-28
Advisory published
2022-03-28
Advisory updated
2022-03-28

Who should care

Organizations running Atlassian Confluence Server, especially internet-facing deployments, and teams responsible for patching, vulnerability management, and incident response.

Technical summary

The vulnerability is described as a pre-authorization arbitrary file read in Atlassian Confluence Server, meaning an attacker may be able to access files without first completing authorization. The supplied corpus does not include a CVSS score or deeper technical details, so remediation guidance should follow the vendor and CISA references.

Defensive priority

High. CISA added this CVE to KEV on 2022-03-28 and set a due date of 2022-04-18, indicating urgent remediation priority for affected environments.

Recommended defensive actions

  • Apply Atlassian updates per vendor instructions.
  • Identify all Confluence Server instances, including internet-facing and shadow deployments.
  • Confirm whether any instance is affected and prioritize patching before or by the CISA due date if still unremediated.
  • Review access logs and file-access related activity on affected systems for signs of misuse.
  • If the product is exposed externally, increase monitoring and restrict access until remediation is complete.

Evidence notes

The supplied corpus identifies the CVE as an Atlassian Confluence Server pre-authorization arbitrary file read and confirms CISA KEV listing, dateAdded 2022-03-28, dueDate 2022-04-18, and known ransomware campaign use marked "Known". No CVSS score was provided in the corpus.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-26085 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-26085

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-26085 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-26085

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.