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CVE-2026-41034 Ascensio CVE debrief

Debrief based on CVE-2026-41034 and source records. ONLYOFFICE DocumentServer before 9.3.0 has an untrusted pointer dereference in XLS processing/conversion, leading to an information leak and ASLR bypass. This vulnerability affects document processing workflows using ONLYOFFICE DocumentServer. Defenders should assess exposure and verify version. The CVE record was published on 2026-04-16T07:16:30.843Z and has not been modified since then. The vulnerability has a medium severity and can lead to potential information leaks and ASLR bypass.

Vendor
Ascensio
Product
ONLYOFFICE DocumentServer
CVSS
MEDIUM 5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-16
Original CVE updated
2026-10-26
Advisory published
2026-04-16
Advisory updated
2026-10-26

Who should care

Defenders of document processing workflows using ONLYOFFICE DocumentServer should assess exposure and verify version. This includes operators, platform administrators, vulnerability management teams, and security teams. They should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Why it matters

CVE-2026-41034 is a medium-severity vulnerability in ONLYOFFICE DocumentServer that can lead to information leaks and ASLR bypass. Defenders of document processing workflows should assess exposure, verify version, and upgrade to 9.3.0 or later if necessary.

  • Potential information leaks in document processing workflows
  • ASLR bypass vulnerability in ONLYOFFICE DocumentServer

Technical summary

ONLYOFFICE DocumentServer before 9.3.0 has an untrusted pointer dereference in XLS processing/conversion, leading to an information leak and ASLR bypass. This vulnerability affects document processing workflows using ONLYOFFICE DocumentServer. The vulnerability has a medium severity and can lead to potential information leaks and ASLR bypass. The CVE record was published on 2026-04-16T07:16:30.843Z and has not been modified since then.

Defensive priority

Assess exposure in document processing workflows.

Recommended defensive actions

  • Assess exposure of document processing workflows to CVE-2026-41034
  • Verify ONLYOFFICE DocumentServer version and upgrade to 9.3.0 or later if necessary
  • Monitor document processing systems for potential information leaks

Evidence notes

Official CVE and NVD records detail an untrusted pointer dereference in ONLYOFFICE DocumentServer before 9.3.0, leading to an information leak and ASLR bypass.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-41034 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-41034

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

  • CVE-2026-41034 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-41034

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

Supplemental references

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.