How severe is CVE-2021-43445?

CVE-2021-43445 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-2021-43445 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43445?

CVE-2021-43445 affects Onlyoffice Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43445?

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-2021-43445 published?

CVE-2021-43445 was published on 2023-01-23 and last updated on 2026-06-17.

CVE-2021-43445

CVE-2021-43445 is a critical-severity vulnerability in Onlyoffice 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 2% (77th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Onlyoffice Server
Published: 2023-01-23
Last modified: 2026-06-17

Description

ONLYOFFICE all versions as of 2021-11-08 is affected by Incorrect Access Control. An attacker can authenticate with the web socket service of the ONLYOFFICE document editor which is protected by JWT auth by using a default JWT signing key.

Frequently asked questions

What is CVE-2021-43445?: ONLYOFFICE all versions as of 2021-11-08 is affected by Incorrect Access Control. An attacker can authenticate with the web socket service of the ONLYOFFICE document editor which is protected by JWT auth by using a default JWT signing key.
How severe is CVE-2021-43445?: CVE-2021-43445 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-2021-43445 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43445?: CVE-2021-43445 affects Onlyoffice Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43445?: 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-2021-43445 published?: CVE-2021-43445 was published on 2023-01-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:onlyoffice:server:*:*:*:*:*:*:*:*

More vulnerabilities in Onlyoffice Server

CVE-2021-43449 — High (CVSS 8.1): ONLYOFFICE all versions as of 2021-11-08 is vulnerable to Server-Side Request Forgery (SSRF). The document editor…
CVE-2021-43447 — High (CVSS 7.5): ONLYOFFICE all versions as of 2021-11-08 is affected by Incorrect Access Control. An authentication bypass in the…
CVE-2021-43444 — High (CVSS 7.5): ONLYOFFICE all versions as of 2021-11-08 is affected by Incorrect Access Control. Signed document download URLs can be…
CVE-2021-43446 — Medium (CVSS 6.1): ONLYOFFICE all versions as of 2021-11-08 is vulnerable to Cross Site Scripting (XSS). The "macros" feature of the…
CVE-2021-43448 — Medium (CVSS 5.3): ONLYOFFICE all versions as of 2021-11-08 is vulnerable to Improper Input Validation. A lack of input validation can…

All CVEs affecting Onlyoffice Server →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-101077 — Critical (CVSS 10.0): A flaw has been found in Netcore NR289-GE 1.4.5102. This impacts the function process_request of the component boa_temp…
CVE-2026-100886 — Critical (CVSS 10.0): A vulnerability was identified in Seetong T8108, T8108P, T8116 and T8232 4.6.1.4-build202604241011. The affected…
CVE-2026-77244 — Critical (CVSS 10.0): MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0,…
CVE-2026-94493 — Critical (CVSS 10.0): A vulnerability was detected in Gigatech PDV5701 1.0.31_240305_112640. This issue affects some unknown processing of…
CVE-2026-83099 — Critical (CVSS 10.0): Vulnerability in the Oracle Forms product of Oracle Fusion Middleware (component: Forms Services, C/S, Charmode).…
CVE-2026-83059 — Critical (CVSS 10.0): Vulnerability in the Oracle Internet Directory product of Oracle Fusion Middleware (component: OID LDAP Server).…

Browse all CWE-287 (Improper Authentication) vulnerabilities →