How severe is CVE-2021-21247?

CVE-2021-21247 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-21247 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21247?

CVE-2021-21247 affects Onedev Project Onedev. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21247?

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-2021-21247 published?

CVE-2021-21247 was published on 2021-01-15 and last updated on 2026-06-17.

CVE-2021-21247

CVE-2021-21247 is a critical-severity vulnerability in Onedev Project Onedev with a CVSS 3.x base score of 9.6. 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-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.6)
CVSS v2: 6.5
EPSS exploit prediction: 2% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Onedev Project Onedev
Published: 2021-01-15
Last modified: 2026-06-17

Description

OneDev is an all-in-one devops platform. In OneDev before version 4.0.3, the application's BasePage registers an AJAX event listener (`AbstractPostAjaxBehavior`) in all pages other than the login page. This listener decodes and deserializes the `data` query parameter. We can access this listener by submitting a POST request to any page. This issue may lead to `post-auth RCE` This endpoint is subject to authentication and, therefore, requires a valid user to carry on the attack. This issue was addressed in 4.0.3 by encrypting serialization payload with secrets only known to server.

Frequently asked questions

What is CVE-2021-21247?: OneDev is an all-in-one devops platform. In OneDev before version 4.0.3, the application's BasePage registers an AJAX event listener (`AbstractPostAjaxBehavior`) in all pages other than the login page. This listener decodes and deserializes the `data` query parameter. We can access this listener by submitting a POST request to any page. This issue may lead to `post-auth RCE` This endpoint is subject to authentication and, therefore, requires a valid user to carry on the attack. This issue was addressed in 4.0.3 by encrypting serialization payload with secrets only known to server.
How severe is CVE-2021-21247?: CVE-2021-21247 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-21247 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21247?: CVE-2021-21247 affects Onedev Project Onedev. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21247?: 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-2021-21247 published?: CVE-2021-21247 was published on 2021-01-15 and last updated on 2026-06-17.

References

https://github.com/theonedev/onedev/security/advisories/GHSA-6pxf-75cf-vwjp

Affected products (1)

cpe:2.3:a:onedev_project:onedev:*:*:*:*:*:*:*:*

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