CVE-2021-21247Public exploitNetwork attack vector

Authenticated code execution via AJAX deserialization

Published Jan 15, 2021 · Updated Aug 3, 2024

Unsafe deserialization in OneDev before 4.0.3 allows remote authenticated users to execute code through a crafted AJAX data parameter. The BasePage AbstractPostAjaxBehavior Base64-decodes the data query parameter and passes the resulting bytes directly to SerializationUtils.deserialize. Any valid account can reach the listener by posting to a non-login page, allowing attacker-controlled code to run in the server process.

CVSS severity9.6
Critical
EPSS probability1.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Unsafe deserialization in OneDev before 4.0.3 allows remote authenticated users to execute code through a crafted AJAX data parameter. The BasePage AbstractPostAjaxBehavior Base64-decodes the data query parameter and passes the resulting bytes directly to SerializationUtils.deserialize. Any valid account can reach the listener by posting to a non-login page, allowing attacker-controlled code to run in the server process.

The record

CVE
CVE-2021-21247
Published
Jan 15, 2021
Updated
Aug 3, 2024
Vendor
OneDev Pty
Product
OneDev
Classifications
CWE-74, CWE-502, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OneDev Pty · OneDevversion=< 4.0.3

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.6GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo