Reference page — cumulative record through Thursday, October 8, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV N L N N U N N H 7.5 .7780 99.6 —
AFFECTED Product Versions Fixed xstream < 1.4.16 – —
TIMELINE Dec 22 Reserved by GitHub_M Mar 22 Published (CNA: GitHub_M) Oct 7 EXPLOIT PUBLISHED — CVE-2021-21341 (x-stream xstream). Public exploit reference added.
XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is vulnerability which may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. No user is affected who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.
| Date | Event | Detail |
|---|---|---|
| December 22, 2020 | Reserved | Reserved by GitHub_M |
| March 22, 2021 | Published | Published (CNA: GitHub_M) |
| October 7, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2021-21341 (x-stream xstream). Public exploit reference added. |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| x-stream | xstream | — | < 1.4.16 | — |
Authoritative record: CVE-2021-21341 at cve.org
Vendors: x-stream
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-21341 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Thursday, October 8, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
