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CVE-2021-39152 XStream

Affected softwareXStream
Severity8.5 High CVSS 3.1 3 scores
Fixed in1.4.18
WeaknessDeserialization of untrusted data (CWE-502)
Published23 Aug 2021
Updated7 Oct 2026

Description

XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker to request data from internal resources that are not publicly available only by manipulating the processed input stream with a Java runtime version 14 to 8. 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](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.18.

CWE-918 · Server-side request forgery

Exploitation status

Exploited

Real-world exploitation reported by VulnCheck KEV. CISA has not confirmed it.

  • CISA KEV not listed
  • VulnCheck KEV listed Exploitation reported in the wild. 1 citation · earliest 2026-02-14.
  • CISA Vulnrichment exploitation: none
  • Indexed PoC 1 indexed Published artifacts you can open, in Nuclei.
  • EPSS 11% chance in 30 days A model's forecast, not a report of exploitation. Higher than 96% of all scored CVEs.

VulnCheck KEV

Exploitation evidence from VulnCheck Known Exploited Vulnerabilities (VulnCheck KEV), used under VulnCheck's community terms. View CVE-2021-39152 in VulnCheck (free account).

EvidenceSourceDetailDate
Reported exploitation labs.greynoise.io /grimoire/2026-02-13-weekly-oast-report 2026-02-14
IndexArtifactStarsFirst seen
Nuclei XStream <1.4.18 - Server-Side Request Forgery

Waratek protection

Mitigation candidate

A kind of vulnerability Waratek's rules address, with exploit code published or exploitation reported. No rule exists and none is planned yet. The decision below says what we found to build a rule from.

  • Protection none
  • Action unverified
  • Review automated Inferred
  • Record active
Decided by A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug
Finding A reference points at an upstream fix (advisory tier): https://github.com/x-stream/xstream/security/advisories/GHSA-xw4p-crpj-vjx2. That makes this CVE a candidate for an ARMR patch rule — it is the kind of defect ARMR can address, and there is a fix to work from. No rule exists and none is scheduled: writing one means reading the linked change and finding a hook point ARMR can express it at, which may turn out not to exist.
Candidate fix https://github.com/x-stream/xstream/security/advisories/GHSA-xw4p-crpj-vjx2 : the maintainers' own security advisory: names the version that fixes it, so the fix is the difference between two releases

CVSS

8.5 HIGH v3.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H 3 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 8.5 HIGH CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H security-advisories@github.com Secondary published
CVSS 3.1 8.5 HIGH CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H NVD Primary
CVSS 2.0 6.0 none AV:N/AC:M/Au:S/C:P/I:P/A:P NVD Primary

Affected software and releases

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
com.thoughtworks.xstream:xstream 0 1.4.18 unbounded

Products and versions

16 products, 36 version entries
SourceVendorProductSchemeAffected versions
osv com.thoughtworks.xstream xstream generic < 1.4.18
nvd debian debian linux generic 9.0 · 10.0 · 11.0
nvd fedoraproject fedora generic 33 · 34 · 35
nvd netapp snapmanager generic any version
nvd oracle business activity monitoring generic 12.2.1.4.0
nvd oracle commerce guided search generic 11.3.2
nvd oracle communications billing and revenue management elastic charging engine generic 11.3 · 12.0
nvd oracle communications cloud native core automated test suite generic 1.9.0
nvd oracle communications cloud native core binding support function generic 1.10.0
nvd oracle communications cloud native core policy generic 1.14.0
nvd oracle communications unified inventory management generic 7.3.4 · 7.3.5 · 7.4.0 · 7.4.1 · 7.4.2
nvd oracle retail xstore point of service generic 16.0.6 · 17.0.4 · 18.0.3 · 19.0.2 · 20.0.1
nvd oracle utilities framework generic 4.2.0.2.0 · 4.2.0.3.0 · 4.3.0.1.0 · 4.3.0.6.0 · 4.4.0.0.0 · 4.4.0.2.0 · 4.4.0.3.0
nvd oracle utilities testing accelerator generic 6.0.0.1.1
nvd oracle webcenter portal generic 12.2.1.3.0 · 12.2.1.4.0
nvd xstream xstream generic < 1.4.18

References

URLTags
https://github.com/x-stream/xstream/security/advisories/GHSA-xw4p-crpj-vjx2 advisory
https://github.com/x-stream/xstream PACKAGE
https://lists.debian.org/debian-lts-announce/2021/09/msg00017.html WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7 WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB WEB
https://security.netapp.com/advisory/ntap-20210923-0003 WEB
https://www.debian.org/security/2021/dsa-5004 WEB
https://www.oracle.com/security-alerts/cpuapr2022.html WEB
https://www.oracle.com/security-alerts/cpujan2022.html WEB

Timeline

Published2021-08-23By the CVE Program.
VulnCheck KEV: earliest evidence2026-02-14Date of the oldest evidence of exploitation in VulnCheck KEV's record. VulnCheck does not publish the date it listed the CVE.
NVD record modified2026-10-07NVD's own last-modified date for this record.