CVE-2021-21349

HIGHNVD 8.68.7▲
EchelonGraph scoreHIGH confidence

Score elevated to 8.7 because EPSS predicts 47% probability of exploitation within the next 30 days (98th percentile of EPSS-scored CVEs). NVD baseline CVSS 8.6 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction (continuous uplift above 30%)
Sources: epss, nvd
Trending — 4 sources updated this weekElevated
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 47%CVSS: 8.6Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability which may allow a remote attacker to request data from internal resources that are not publicly available 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.

CVSS v3
8.6
EG Score
8.7HIGHhigh confidence
EG Risk
73
EG Risk 73/100CISA 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
Severity87% × 45%
Exploitation47% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
47%
EPSS %ILE
98th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

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

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (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

March 23, 2021

Last Modified

October 7, 2026

Advisory Details (10)

Auto-updated Oct 7, 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-20210430-0002/
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 2616-1] libxstream-java security update

https://lists.debian.org/debian-lts-announce/2021/04/msg00002.html
generic

Pony Mail

https://lists.apache.org/thread.html/r9ac71b047767205aa22e3a08cb33f3e0586de6b2fac48b425c6e16b0%40%3Cdev.jmeter.apache.org%3E
generic

Pony Mail

https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd%40%3Cusers.activemq.apache.org%3E
githubMentions a patch (unverified)

A Server-Side Forgery Request can be activated unmarshalling with XStream to access data streams from an arbitrary URL referencing a resource in an intranet or the local host · Advisory · x-stream/xstream · GitHub

https://github.com/x-stream/xstream/security/advisories/GHSA-f6hm-88x3-mfjv
generic

XStream - Change History

http://x-stream.github.io/changes.html#1.4.16

Vendor Advisories for CVE-2021-21349(5)

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 (1.4.15-1ubuntu0.1) @ hirsute2026-10-07ubuntu
ubuntulibxstream-java (1.4.7-1ubuntu0.1+esm2) @ trusty2026-10-07ubuntu
redhatpatch2022-03-23redhat
redhatxstream2021-12-14redhat
redhatpatch2021-11-23redhat

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

(6 across 6 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java—
  • every version up to 1.4.15-2: fixed in 1.4.15-2
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java—
  • every version up to 1.4.15-2: fixed in 1.4.15-2
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java—
  • every version up to 1.4.15-2: fixed in 1.4.15-2
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java—
  • every version up to 1.4.15-2: fixed in 1.4.15-2
—
Debian:9(1)
PackageVulnerable rangeFix by version rangeDependents
libxstream-java1.4.10-1 ... 1.4.9-2+deb9u1 (6 versions)
  • every version up to 1.4.11.1-1+deb9u2: fixed in 1.4.11.1-1+deb9u2
—
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
com.thoughtworks.xstream:xstream0.1 ... 1.4.9 (40 versions)
  • every version up to 1.4.16: fixed in 1.4.16
—

Weakness Classification(2)

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

Additional Vendor Advisories

(3)

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 9× in last 7d / 31× 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 157 total refreshes for this CVE.

  1. 2026-10-09 20:04 UTCEPSS rescore
  2. 2026-10-08 16:39 UTCEPSS rescore
  3. 2026-10-07 23:44 UTCEPSS rescore
  4. 2026-10-07 19:28 UTCEG score recompute▲ 1.70
  5. 2026-10-07 19:28 UTCVendor advisory
  6. 2026-10-07 19:19 UTCNVD updateCVSS v3 → 8.6 · severity → HIGH
  7. 2026-10-07 19:03 UTCEG score recompute
  8. 2026-10-07 19:03 UTCVendor advisory
  9. 2026-10-06 15:13 UTCEPSS rescore
  10. 2026-10-02 16:22 UTCEPSS rescore
  11. 2026-10-01 19:46 UTCEPSS rescore
  12. 2026-09-30 15:29 UTCEG score recompute
  13. 2026-09-30 15:00 UTCEPSS rescore
  14. 2026-09-28 13:47 UTCEPSS rescore
  15. 2026-09-27 13:41 UTCEPSS rescore
  16. 2026-09-26 15:54 UTCEPSS rescore
  17. 2026-09-26 15:54 UTCEPSS rescore
  18. 2026-09-26 07:25 UTCOSV refresh
  19. 2026-09-26 00:21 UTCEPSS rescore
  20. 2026-09-24 14:00 UTCEPSS rescore
  21. 2026-09-24 14:00 UTCEPSS rescore
  22. 2026-09-23 13:44 UTCEPSS rescore
  23. 2026-09-22 14:44 UTCEPSS rescore
  24. 2026-09-21 20:28 UTCEPSS rescore
  25. 2026-09-18 19:23 UTCEPSS rescore
Show 75 more
  1. 2026-09-17 19:23 UTCEPSS rescore
  2. 2026-09-16 14:05 UTCEPSS rescore
  3. 2026-09-16 14:04 UTCEPSS rescore
  4. 2026-09-15 03:06 UTCEPSS rescore
  5. 2026-09-12 14:57 UTCEPSS rescore
  6. 2026-09-10 09:29 UTCEPSS rescore
  7. 2026-09-08 21:56 UTCEPSS rescore
  8. 2026-09-06 21:01 UTCOSV refresh
  9. 2026-09-06 13:44 UTCEPSS rescore
  10. 2026-09-06 13:44 UTCEPSS rescore
  11. 2026-09-05 15:25 UTCEPSS rescore
  12. 2026-09-04 13:57 UTCEPSS rescore
  13. 2026-09-04 05:03 UTCEPSS rescore
  14. 2026-09-02 14:08 UTCEPSS rescore
  15. 2026-09-01 13:50 UTCEPSS rescore
  16. 2026-09-01 03:32 UTCEPSS rescore
  17. 2026-08-30 19:14 UTCEPSS rescore
  18. 2026-08-30 01:19 UTCEPSS rescore
  19. 2026-08-28 21:37 UTCEPSS rescore
  20. 2026-08-26 14:42 UTCEPSS rescore
  21. 2026-08-25 13:45 UTCEPSS rescore
  22. 2026-08-21 23:46 UTCEPSS rescore
  23. 2026-08-20 22:52 UTCEPSS rescore
  24. 2026-08-20 06:55 UTCOSV refresh
  25. 2026-08-19 17:01 UTCEPSS rescore
  26. 2026-08-18 13:45 UTCEPSS rescore
  27. 2026-08-17 13:43 UTCEPSS rescore
  28. 2026-08-16 02:11 UTCEPSS rescore
  29. 2026-08-15 01:27 UTCEPSS rescore
  30. 2026-08-13 21:57 UTCEPSS rescore
  31. 2026-08-12 13:47 UTCEPSS rescore
  32. 2026-08-11 13:38 UTCEPSS rescore
  33. 2026-08-07 16:23 UTCEPSS rescore
  34. 2026-08-06 13:43 UTCEPSS rescore
  35. 2026-08-05 19:14 UTCEPSS rescore
  36. 2026-08-05 02:10 UTCOSV refresh
  37. 2026-08-03 10:32 UTCEPSS rescore
  38. 2026-08-01 04:12 UTCEPSS rescore
  39. 2026-07-30 16:25 UTCEPSS rescore
  40. 2026-07-30 01:27 UTCEPSS rescore
  41. 2026-07-30 01:27 UTCEPSS rescore
  42. 2026-07-26 14:52 UTCEPSS rescore
  43. 2026-07-25 14:15 UTCEPSS rescore
  44. 2026-07-24 14:15 UTCEPSS rescore
  45. 2026-07-23 01:57 UTCEG score recompute▲ 0.90
  46. 2026-07-22 22:43 UTCEG score recompute
  47. 2026-07-22 14:05 UTCEPSS rescore
  48. 2026-07-21 15:22 UTCEPSS rescore
  49. 2026-07-21 15:22 UTCEPSS rescore
  50. 2026-07-20 17:04 UTCEPSS rescore
  51. 2026-07-19 02:26 UTCEPSS rescore
  52. 2026-07-18 23:59 UTCOSV refresh
  53. 2026-07-16 17:00 UTCEPSS rescore
  54. 2026-07-15 16:55 UTCEPSS rescore
  55. 2026-07-15 16:55 UTCEPSS rescore
  56. 2026-07-13 22:27 UTCEPSS rescore
  57. 2026-07-13 22:27 UTCEPSS rescore
  58. 2026-07-13 06:10 UTCEPSS rescore
  59. 2026-07-13 06:10 UTCEPSS rescore
  60. 2026-07-12 05:44 UTCEPSS rescore
  61. 2026-07-12 05:44 UTCEPSS rescore
  62. 2026-07-11 08:25 UTCEPSS rescore
  63. 2026-07-09 19:07 UTCEPSS rescore
  64. 2026-07-07 13:43 UTCEPSS rescore
  65. 2026-07-06 16:25 UTCEPSS rescore
  66. 2026-07-06 02:21 UTCEPSS rescore
  67. 2026-07-06 02:21 UTCEPSS rescore
  68. 2026-07-02 16:57 UTCEPSS rescore
  69. 2026-07-01 15:03 UTCEPSS rescore
  70. 2026-07-01 06:48 UTCOSV refresh
  71. 2026-06-29 14:04 UTCEPSS rescore
  72. 2026-06-29 14:04 UTCEPSS rescore
  73. 2026-06-28 04:54 UTCEPSS rescore
  74. 2026-06-28 04:54 UTCEPSS rescore
  75. 2026-06-27 03:06 UTCEPSS rescore

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

Frequently asked(5)

What is CVE-2021-21349?
CVE-2021-21349 is a high vulnerability published on March 23, 2021. XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability which may allow a remote attacker to request data from internal resources that are not publicly available only by manipulating the processed input stream. No user is…
When was CVE-2021-21349 disclosed?
CVE-2021-21349 was first published on March 23, 2021, with the most recent update on October 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-21349 actively exploited?
CVE-2021-21349 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 47% probability of exploitation in the next 30 days (98th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-21349?
CVE-2021-21349 has a CVSS v3 base score of 8.6 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 8.7 (HIGH).
How do I remediate CVE-2021-21349?
A fix for CVE-2021-21349 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-21349 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-21349

Explore →

Is Your Infrastructure Affected by CVE-2021-21349?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs