CVE-2021-25641
9.8
CRITICAL · CVSS 3.1 · EPSS 21.2% (pctl 98)
Patch early
EPSS 21.2% — above the 10% action threshold.
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.
Scoring
| CVSS | 9.8 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 21.22% — more likely to be exploited than 98% of all CVEs |
| Weakness | CWE-502 |
| On CISA KEV | no |
| Public exploit | none known |
| Published | 2021-06-01 |
| Last modified | 2026-06-17 |
Affected (1)
| Vendor | Product |
|---|---|
| apache | dubbo |
References
→ the Explorer · watch your stack · NVD