CVE-2021-39144

CRITICALNVD 8.59.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2023-03-10), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.5 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, nvd
Trending — 3 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 98%CVSS: 8.5Exploit: cisa kev · ssvc active · Metasploit · epss top5pct · epss high · public exploitExposed services: Not assessed

A fix is available — apply it.

XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker has sufficient rights to execute commands of the host 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. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.

CVSS v3
8.5
EG Score
9.0CRITICALhigh confidence
EG Risk
81
EG Risk 81/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Attend at medium and Act at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.
EPSS PROB
98%
EPSS %ILE
99th
KEV
⚠ Exploited

CISA SSVCTrack at low, Attend at medium and Act at high mission impact.

A fix is available. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.

Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 23, 2021

Last Modified

October 24, 2025

Advisory Details (8)

Auto-updated Jun 2, 2026
Patch available. Sources: github.
generic

[SECURITY] [DSA 5004-1] libxstream-java security update

https://www.debian.org/security/2021/dsa-5004
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20210923-0003/
generic

[SECURITY] Fedora 34 Update: xstream-1.4.18-2.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/
generic

[SECURITY] Fedora 35 Update: xstream-1.4.18-2.fc35 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/
generic

[SECURITY] Fedora 33 Update: xstream-1.4.18-2.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/
genericMentions a patch (unverified)

[SECURITY] [DLA 2769-1] libxstream-java security update

https://lists.debian.org/debian-lts-announce/2021/09/msg00017.html
githubMentions a patch (unverified)

XStream is vulnerable to a Remote Command Execution attack · Advisory · x-stream/xstream · GitHub

https://github.com/x-stream/xstream/security/advisories/GHSA-j9h8-phrw-h4fh
generic

Packet Storm

http://packetstormsecurity.com/files/169859/VMware-NSX-Manager-XStream-Unauthenticated-Remote-Code-Execution.html

Vendor Advisories for CVE-2021-39144(8)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(5)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibxstream-java (1.4.7-1ubuntu0.1+esm1) @ trusty2026-10-10ubuntu
redhatrh-sso7-keycloak2023-06-27redhat
redhatxstream2023-03-17redhat
redhatpatch2021-11-23redhat
redhatxstream-0:1.3.1-16.el7_92021-10-25redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(7 across 7 ecosystems)
Debian:10(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java1.4.11.1-1, 1.4.11.1-1+deb10u1, 1.4.11.1-1+deb10u2
  • every version up to 1.4.11.1-1+deb10u3: fixed in 1.4.11.1-1+deb10u3
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java1.4.15-3
  • every version up to 1.4.15-3+deb11u1: fixed in 1.4.15-3+deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java—
  • every version up to 1.4.18-1: fixed in 1.4.18-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java—
  • every version up to 1.4.18-1: fixed in 1.4.18-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java—
  • every version up to 1.4.18-1: fixed in 1.4.18-1
—
Debian:9(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java1.4.10-1 ... 1.4.9-2+deb9u1 (8 versions)
  • every version up to 1.4.11.1-1+deb9u4: fixed in 1.4.11.1-1+deb9u4
—
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
com.thoughtworks.xstream:xstream0.1 ... 1.4.9 (42 versions)
  • every version up to 1.4.18: fixed in 1.4.18
—

Weakness Classification(3)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 47× in last 7d / 217× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 939 total refreshes for this CVE.

  1. 2026-10-10 10:12 UTCVendor advisory
  2. 2026-10-10 06:27 UTCVendor advisory
  3. 2026-10-10 02:42 UTCVendor advisory
  4. 2026-10-09 22:57 UTCVendor advisory
  5. 2026-10-09 19:12 UTCVendor advisory
  6. 2026-10-09 15:28 UTCVendor advisory
  7. 2026-10-09 11:43 UTCVendor advisory
  8. 2026-10-09 07:57 UTCVendor advisory
  9. 2026-10-09 04:12 UTCVendor advisory
  10. 2026-10-09 00:27 UTCVendor advisory
  11. 2026-10-08 20:42 UTCVendor advisory
  12. 2026-10-08 16:57 UTCVendor advisory
  13. 2026-10-08 13:12 UTCVendor advisory
  14. 2026-10-08 09:25 UTCVendor advisory
  15. 2026-10-08 05:40 UTCVendor advisory
  16. 2026-10-08 01:54 UTCEG score recompute
  17. 2026-10-08 01:54 UTCVendor advisory
  18. 2026-10-07 23:44 UTCEPSS rescore
  19. 2026-10-07 22:09 UTCVendor advisory
  20. 2026-10-07 18:23 UTCVendor advisory
  21. 2026-10-07 14:37 UTCVendor advisory
  22. 2026-10-07 10:53 UTCVendor advisory
  23. 2026-10-07 07:08 UTCVendor advisory
  24. 2026-10-07 03:23 UTCVendor advisory
  25. 2026-10-06 23:38 UTCVendor advisory
Show 75 more
  1. 2026-10-06 19:53 UTCVendor advisory
  2. 2026-10-06 16:08 UTCVendor advisory
  3. 2026-10-06 12:23 UTCVendor advisory
  4. 2026-10-06 08:38 UTCVendor advisory
  5. 2026-10-06 04:50 UTCVendor advisory
  6. 2026-10-06 01:05 UTCVendor advisory
  7. 2026-10-05 21:18 UTCVendor advisory
  8. 2026-10-05 17:32 UTCVendor advisory
  9. 2026-10-05 13:47 UTCVendor advisory
  10. 2026-10-05 10:03 UTCVendor advisory
  11. 2026-10-05 06:18 UTCVendor advisory
  12. 2026-10-05 02:33 UTCVendor advisory
  13. 2026-10-04 22:49 UTCVendor advisory
  14. 2026-10-04 19:04 UTCVendor advisory
  15. 2026-10-04 15:18 UTCVendor advisory
  16. 2026-10-04 11:33 UTCVendor advisory
  17. 2026-10-04 07:48 UTCVendor advisory
  18. 2026-10-04 04:03 UTCVendor advisory
  19. 2026-10-04 00:18 UTCVendor advisory
  20. 2026-10-03 20:34 UTCVendor advisory
  21. 2026-10-03 16:48 UTCVendor advisory
  22. 2026-10-03 13:04 UTCVendor advisory
  23. 2026-10-03 09:19 UTCVendor advisory
  24. 2026-10-03 05:35 UTCVendor advisory
  25. 2026-10-03 01:49 UTCVendor advisory
  26. 2026-10-02 22:05 UTCVendor advisory
  27. 2026-10-02 18:20 UTCVendor advisory
  28. 2026-10-02 14:36 UTCVendor advisory
  29. 2026-10-02 10:50 UTCVendor advisory
  30. 2026-10-02 07:05 UTCVendor advisory
  31. 2026-10-02 03:21 UTCVendor advisory
  32. 2026-10-01 23:36 UTCVendor advisory
  33. 2026-10-01 19:50 UTCVendor advisory
  34. 2026-10-01 16:06 UTCVendor advisory
  35. 2026-10-01 12:21 UTCVendor advisory
  36. 2026-10-01 08:34 UTCVendor advisory
  37. 2026-10-01 04:50 UTCVendor advisory
  38. 2026-10-01 01:03 UTCVendor advisory
  39. 2026-09-30 21:18 UTCVendor advisory
  40. 2026-09-30 17:32 UTCVendor advisory
  41. 2026-09-30 13:47 UTCVendor advisory
  42. 2026-09-30 10:03 UTCVendor advisory
  43. 2026-09-30 06:19 UTCVendor advisory
  44. 2026-09-30 02:34 UTCVendor advisory
  45. 2026-09-29 22:49 UTCVendor advisory
  46. 2026-09-29 19:01 UTCVendor advisory
  47. 2026-09-29 15:14 UTCVendor advisory
  48. 2026-09-29 11:28 UTCVendor advisory
  49. 2026-09-29 07:43 UTCVendor advisory
  50. 2026-09-29 03:58 UTCVendor advisory
  51. 2026-09-29 00:10 UTCEG score recompute
  52. 2026-09-29 00:10 UTCVendor advisory
  53. 2026-09-28 20:26 UTCVendor advisory
  54. 2026-09-28 16:41 UTCVendor advisory
  55. 2026-09-28 12:55 UTCVendor advisory
  56. 2026-09-28 09:10 UTCVendor advisory
  57. 2026-09-28 05:26 UTCVendor advisory
  58. 2026-09-28 01:41 UTCVendor advisory
  59. 2026-09-27 21:53 UTCVendor advisory
  60. 2026-09-27 21:51 UTCCISA KEV update
  61. 2026-09-27 18:06 UTCVendor advisory
  62. 2026-09-27 14:21 UTCVendor advisory
  63. 2026-09-27 10:36 UTCVendor advisory
  64. 2026-09-27 06:45 UTCVendor advisory
  65. 2026-09-27 03:00 UTCVendor advisory
  66. 2026-09-26 23:15 UTCVendor advisory
  67. 2026-09-26 19:28 UTCVendor advisory
  68. 2026-09-26 15:43 UTCVendor advisory
  69. 2026-09-26 11:58 UTCVendor advisory
  70. 2026-09-26 08:13 UTCVendor advisory
  71. 2026-09-26 04:27 UTCVendor advisory
  72. 2026-09-26 00:41 UTCEG score recompute
  73. 2026-09-26 00:41 UTCVendor advisory
  74. 2026-09-26 00:21 UTCEPSS rescore
  75. 2026-09-25 20:54 UTCVendor advisory

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 Metasploit module). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Metasploitexploit/linux/http/vmware_nsxmgr_xstream_rce_cve_2021_39144✓ verified
    First seen Oct 25, 2022

    VMware NSX Manager XStream unauthenticated RCE

    Open source ↗
  • Nucleihttp/cves/2021/CVE-2021-39144.yaml
    First seen Jan 1, 2021

    XStream 1.4.18 - Remote Code Execution

    Open source ↗

Related CVEs(same product + same vendor + same CWE)

Frequently asked(6)

What is CVE-2021-39144?
CVE-2021-39144 is a critical vulnerability published on August 23, 2021. XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker has sufficient rights to execute commands of the host only by manipulating the processed input stream. No user is affected, who followed the recommendation to…
When was CVE-2021-39144 disclosed?
CVE-2021-39144 was first published on August 23, 2021, with the most recent update on October 24, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-39144 actively exploited?
Yes. CISA added CVE-2021-39144 to the Known Exploited Vulnerabilities catalog on March 10, 2023, affecting XStream XStream. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is available. Apply it.
What is the CVSS score of CVE-2021-39144?
CVE-2021-39144 has a CVSS v3 base score of 8.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
Which products are affected by CVE-2021-39144?
CVE-2021-39144 affects XStream XStream. The affected packages EchelonGraph has on record, with version ranges, are listed in the Affected Packages section of this page.
How do I remediate CVE-2021-39144?
A fix for CVE-2021-39144 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-39144 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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