How severe is CVE-2023-34939?

CVE-2023-34939 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-2023-34939 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-34939?

CVE-2023-34939 affects Onlyoffice. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-34939?

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-2023-34939 published?

CVE-2023-34939 was published on 2023-06-22 and last updated on 2026-06-17.

CVE-2023-34939

CVE-2023-34939 is a critical-severity vulnerability in Onlyoffice 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-22.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Onlyoffice
Published: 2023-06-22
Last modified: 2026-06-17

Description

Onlyoffice Community Server before v12.5.2 was discovered to contain a remote code execution (RCE) vulnerability via the component UploadProgress.ashx.

Frequently asked questions

What is CVE-2023-34939?: Onlyoffice Community Server before v12.5.2 was discovered to contain a remote code execution (RCE) vulnerability via the component UploadProgress.ashx.
How severe is CVE-2023-34939?: CVE-2023-34939 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-2023-34939 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-34939?: CVE-2023-34939 affects Onlyoffice. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-34939?: 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-2023-34939 published?: CVE-2023-34939 was published on 2023-06-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:onlyoffice:onlyoffice:*:*:*:*:community_server:*:*:*

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