CVE-2020-11534

CVE-2020-11534 is a critical-severity vulnerability in Onlyoffice Document Server with a CVSS 3.x base score of 9.8. 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-20.

Key facts

• Severity: Critical (CVSS 3.x base score 9.8)
• CVSS v2: 7.5
• EPSS exploit prediction: 2% (81st percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-20
• Affected product: Onlyoffice Document Server
• Published: 2020-04-15
• Last modified: 2026-06-17

Description

An issue was discovered in ONLYOFFICE Document Server 5.5.0. An attacker can craft a malicious .docx file, and exploit the NSFileDownloader function to pass parameters to a binary (such as curl or wget) and remotely execute code on a victim's server.

Frequently asked questions

What is CVE-2020-11534?

An issue was discovered in ONLYOFFICE Document Server 5.5.0. An attacker can craft a malicious .docx file, and exploit the NSFileDownloader function to pass parameters to a binary (such as curl or wget) and remotely execute code on a victim's server.

How severe is CVE-2020-11534?

CVE-2020-11534 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-11534 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-11534?

CVE-2020-11534 affects Onlyoffice Document Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-11534?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-11534 published?

CVE-2020-11534 was published on 2020-04-15 and last updated on 2026-06-17.

References

• https://gist.github.com/andrewaeva/beb92d3d2f1c5672dbda5050e323f6a0
• https://github.com/ONLYOFFICE/DocumentServer/blob/master/CHANGELOG.md#551

Affected products (1)

• cpe:2.3:a:onlyoffice:document_server:5.5.0:*:*:*:*:*:*:*

More vulnerabilities in Onlyoffice Document Server

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• CVE-2022-29777 — Critical (CVSS 9.8): Onlyoffice Document Server v6.0.0 and below and Core 6.1.0.26 and below were discovered to contain a heap overflow via…
• CVE-2022-29776 — Critical (CVSS 9.8): Onlyoffice Document Server v6.0.0 and below and Core 6.1.0.26 and below were discovered to contain a stack overflow via…
• CVE-2021-25833 — Critical (CVSS 9.8): A file extension handling issue was found in [server] module of ONLYOFFICE DocumentServer v4.2.0.71-v5.6.0.21. The file…
• CVE-2021-25832 — Critical (CVSS 9.8): A heap buffer overflow vulnerability inside of BMP image processing was found at [core] module of ONLYOFFICE…

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