CVE-2021-3518

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under NVD CVSS v3. EPSS exploit probability: 3.7%, top 12% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 4%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

There's a flaw in libxml2 in versions before 2.9.11. An attacker who is able to submit a crafted file to be processed by an application linked with libxml2 could trigger a use-after-free. The greatest impact from this flaw is to confidentiality, integrity, and availability.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: Track

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
Severity88% × 45%
Exploitation4% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
4%
EPSS %ILE
89%
KEV
Not listed

Published

May 18, 2021

Last Modified

November 21, 2024

Advisory Details (10)

Auto-updated Aug 25, 2026
Patch available. Sources: redhat.
generic

[SECURITY] Fedora 34 Update: libxml2-2.9.10-12.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QVM4UJ3376I6ZVOYMHBNX4GY3NIV52WV/
generic

[SECURITY] Fedora 33 Update: libxml2-2.9.12-4.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BZOMV5J4PMZAORVT64BKLV6YIZAFDGX6/
generic Patch Available

[SECURITY] [DLA 2653-1] libxml2 security update

https://lists.debian.org/debian-lts-announce/2021/05/msg00008.html
generic
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
generic
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
redhat Patch Available

1954242 – (CVE-2021-3518) CVE-2021-3518 libxml2: Use-after-free in xmlXIncludeDoProcess() in xinclude.c

Affected: Red Hat Enterprise Linux 6 and 7. To learn more about Red Hat Enterprise Linux support life cycles, please see

https://bugzilla.redhat.com/show_bug.cgi?id=1954242
generic

Full Disclosure: APPLE-SA-2021-07-21-6 tvOS 14.7

http://seclists.org/fulldisclosure/2021/Jul/59
generic

Full Disclosure: APPLE-SA-2021-07-21-5 watchOS 7.6

http://seclists.org/fulldisclosure/2021/Jul/58
generic

Full Disclosure: APPLE-SA-2021-07-21-2 macOS Big Sur 11.5

http://seclists.org/fulldisclosure/2021/Jul/55
generic

Full Disclosure: APPLE-SA-2021-07-21-1 iOS 14.7 and iPadOS 14.7

http://seclists.org/fulldisclosure/2021/Jul/54

Vendor Advisories for CVE-2021-3518(4)

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 / EcosystemFixed in / PatchReleasedSource
ubuntupython-libxml2 (2.9.1+dfsg1-3ubuntu4.13+esm2) @ trusty2026-05-26ubuntu
redhatlibxml22022-04-20redhat
redhatjbcs-httpd24-openssl-pkcs11-0:0.4.10-26.jbcs.el72022-04-20redhat
redhatrhmtc/openshift-velero-plugin-rhel8:v1.4.6-42021-07-21redhat
redhatlibxml2-0:2.9.7-9.el8_4.22021-06-29redhat

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

(21 across 21 ecosystems)
Alpine:v3.10(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.9-r5—
Alpine:v3.11(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.10-r5—
Alpine:v3.12(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.10-r6—
Alpine:v3.13(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.10-r7—
Alpine:v3.14(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.15(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.16(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.17(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.18(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.19(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.20(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.11-r0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.10+dfsg-6.6—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.10+dfsg-6.6—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.10+dfsg-6.6—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libxml2—2.9.10+dfsg-6.6—
Debian:9(1)
PackageVulnerable rangeFixed inDependents
libxml22.9.4+dfsg1-2.2, 2.9.4+dfsg1-2.2+deb9u1, 2.9.4+dfsg1-2.2+deb9u2, 2.9.4+dfsg1-2.2+deb9u32.9.4+dfsg1-2.2+deb9u4—
RubyGems(1)
PackageVulnerable rangeFixed inDependents
nokogiri1.0.0 ... 1.9.1 (128 versions)1.11.4—

Weakness Classification(1)

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

Additional Vendor Advisories

(2)

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 6× in last 7d / 30× 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 166 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2021-3518?
CVE-2021-3518 is a high vulnerability published on May 18, 2021. There's a flaw in libxml2 in versions before 2.9.11. An attacker who is able to submit a crafted file to be processed by an application linked with libxml2 could trigger a use-after-free. The greatest impact from this flaw is to confidentiality, integrity, and availability.
When was CVE-2021-3518 disclosed?
CVE-2021-3518 was first published in the National Vulnerability Database on May 18, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-3518 actively exploited?
CVE-2021-3518 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4% probability of exploitation in the next 30 days, which ranks it in the top 10.9% of all scored CVEs.
What is the CVSS score of CVE-2021-3518?
CVE-2021-3518 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2021-3518?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3518, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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