CVE-2021-21342
In XStream before version 1.4.16, there is a vulnerability where the processed stream at unmarshalling time contains type information to recreate the formerly written objects.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 50.0%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability where the processed stream at unmarshalling time contains type information to recreate the formerly written objects. XStream creates therefore new instances based on these type information. An attacker can manipulate the processed input stream and replace or inject objects, that result in a server-side forgery request. 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.
- CVSS 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 49.99% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-502, CWE-918
- Affected
- netapp/oncommand insight · apache/activemq · apache/jmeter · xstream/xstream · debian/debian linux · fedoraproject/fedora · oracle/banking enterprise default management · oracle/banking platform · oracle/banking virtual account management · oracle/business activity monitoring · oracle/communications brm - elastic charging engine · oracle/communications policy management · oracle/communications unified inventory management · oracle/retail xstore point of service · oracle/webcenter portal
- Source
- security-advisories@github.com
EPSS 50.0% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://x-stream.github.io/changes.html#1.4.16Release Notes, Third Party Advisory
- https://github.com/x-stream/xstream/security/advisories/GHSA-hvv8-336g-rx3mThird Party Advisory
- https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd%40%3Cusers.activemq.apache.org%3EIssue Tracking, Mailing List, Third Party Advisory
- https://lists.apache.org/thread.html/r9ac71b047767205aa22e3a08cb33f3e0586de6b2fac48b425c6e16b0%40%3Cdev.jmeter.apache.org%3EIssue Tracking, Mailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/04/msg00002.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/Mailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210430-0002/Third Party Advisory
- https://www.debian.org/security/2021/dsa-5004Mailing List, Third Party Advisory
- https://www.oracle.com//security-alerts/cpujul2021.htmlThird Party Advisory
- https://www.oracle.com/security-alerts/cpujan2022.htmlNot Applicable, Patch, Vendor Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlThird Party Advisory
- https://x-stream.github.io/CVE-2021-21342.htmlExploit, Third Party Advisory
- https://x-stream.github.io/security.html#workaroundMitigation, Third Party Advisory
- http://x-stream.github.io/changes.html#1.4.16Release Notes, Third Party Advisory
- https://github.com/x-stream/xstream/security/advisories/GHSA-hvv8-336g-rx3mThird Party Advisory
- https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd%40%3Cusers.activemq.apache.org%3EIssue Tracking, Mailing List, Third Party Advisory
- https://lists.apache.org/thread.html/r9ac71b047767205aa22e3a08cb33f3e0586de6b2fac48b425c6e16b0%40%3Cdev.jmeter.apache.org%3EIssue Tracking, Mailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/04/msg00002.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/Mailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210430-0002/Third Party Advisory
- https://www.debian.org/security/2021/dsa-5004Mailing List, Third Party Advisory
- https://www.oracle.com//security-alerts/cpujul2021.htmlThird Party Advisory
- https://www.oracle.com/security-alerts/cpujan2022.htmlNot Applicable, Patch, Vendor Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlThird Party Advisory
- https://x-stream.github.io/CVE-2021-21342.htmlExploit, Third Party Advisory
- https://x-stream.github.io/security.html#workaroundMitigation, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.