CVE-2021-25641
Dubbo Zookeeper does not check serialization id
- Published
- Updated
- Reserved
- Assigned by
- apache
Description
Each Apache Dubbo server will set a serialization id to tell the clients which serialization protocol it is working on. But for Dubbo versions before 2.7.8 or 2.6.9, an attacker can choose which serialization id the Provider will use by tampering with the byte preamble flags, aka, not following the server's instruction. This means that if a weak deserializer such as the Kryo and FST are somehow in code scope (e.g. if Kryo is somehow a part of a dependency), a remote unauthenticated attacker can tell the Provider to use the weak deserializer, and then proceed to exploit it.
Timeline
ID reserved
By apache
- 4 months later
· 4 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 21.2% · top 2.4% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Weakness
- Remote Code Execution by tempering the serialization id on server side.
- CWE-502 (opens in a new tab)All about CWE-502 and its CVEs
Affected products
Apache Software Foundation · Apache Dubbo
- affected Apache Dubbo 2.7.x – < 2.7.8
- affected Apache Dubbo 2.6.x – < 2.6.9
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavencom.alibaba:dubboGHSA-v2rg-8cwr-75g8 (opens in a new tab)
- Mavenorg.apache.dubbo:dubboGHSA-v2rg-8cwr-75g8 (opens in a new tab)
References (1)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-v2rg-8cwr-75g8 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-25641)Record last updated .