CVE-2026-4224

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory published 2026-03-16. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

When an Expat parser with a registered ElementDeclHandler parses an inline document type definition containing a deeply nested content model a C stack overflow occurs.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
34
EG Risk 34/100

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
Severity75% × 45%
Exploitation1% × 40%
Automatability0% × 15%
EPSS PROB
0.7%
EPSS %ILE
51st
KEV
Not listed

Published

March 16, 2026

Last Modified

August 13, 2026

Advisory Details (9)

Auto-updated Aug 2, 2026
Patch available. Sources: github_commit, github_pr.
generic

oss-security - [CVE-2026-4224] CPython Stack overflow parsing XML with deeply nested DTD content models

http://www.openwall.com/lists/oss-security/2026/03/16/4
generic

Mailman 3 [CVE-2026-4224] Stack overflow parsing XML with deeply nested DTD content models - Security-announce - python.org

https://mail.python.org/archives/list/[email protected]/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/
github_pr

gh-145986: Avoid unbound C recursion in `conv_content_model` in `pyexpat.c` (CVE 2026-4224)

Fix merged in python/cpython PR #145987 on 2026-03-15 — awaiting tagged release

https://github.com/python/cpython/pull/145987
generic

`pyexpat.c`: Unbounded C recursion in `conv_content_model` causes crash (CVE 2026-4224) · Issue #145986 · python/cpython · GitHub

https://github.com/python/cpython/issues/145986
github_commit

commit eb0e8be3a7e1 (python/cpython)

Fix landed in python/cpython commit eb0e8be3a7e1 — awaiting tagged release

https://github.com/python/cpython/commit/eb0e8be3a7e11b87d198a2c3af1ed0eccf532768
github_commit

commit e0a8a6da9059 (python/cpython)

Fix landed in python/cpython commit e0a8a6da9059 — awaiting tagged release

https://github.com/python/cpython/commit/e0a8a6da90597a924b300debe045cdb4628ee1f3
github_commit

commit af856a717732 (python/cpython)

Fix landed in python/cpython commit af856a717732 — awaiting tagged release

https://github.com/python/cpython/commit/af856a7177326ac25d9f66cc6dd28b554d914fee
github_commit

commit 642865ddf4b2 (python/cpython)

Fix landed in python/cpython commit 642865ddf4b2 — awaiting tagged release

https://github.com/python/cpython/commit/642865ddf4b232da1f3b1f7abcfa3254c4bfe785
github_commit

commit 196edfb06a74 (python/cpython)

Fix landed in python/cpython commit 196edfb06a74 — awaiting tagged release

https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4a

Vendor Advisories for CVE-2026-4224(13)

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

Patch Availability(11)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntupython3.12-venv (3.12.3-1ubuntu0.15) @ noble2026-08-05ubuntu
redhatrhui5/rhua-rhel9:17797982222026-05-27redhat
redhatpython3.12-0:3.12.13-2.el9_82026-05-19redhat
redhatpython3.12-0:3.12.13-2.el10_22026-05-19redhat
redhatpython3.14-0:3.14.4-2.el10_22026-05-19redhat
redhatpython3.14-0:3.14.4-2.el9_82026-05-19redhat
redhatpython3.12-0:3.12.13-2.el8_102026-04-27redhat
redhatpython3-12-main-3.12.13-3.hum12026-04-17redhat
redhatpython3-11-main-3.11.15-4.hum12026-04-17redhat
redhatpython3-14-main-3.14.4-1.hum12026-04-11redhat
redhatpython3-13-main-3.13.13-1.hum12026-04-10redhat

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

(10 across 8 ecosystems)
Debian:11(2)
PackageVulnerable rangeFix by version rangeDependents
python2.72.7.18-10 ... 2.7.18-9 (10 versions)
  • every version on: no fix on record
—
python3.93.9.2-1 ... 3.9.2-1+deb11u6 (7 versions)
  • every version up to 3.9.2-1+deb11u7: fixed in 3.9.2-1+deb11u7
—
Debian:14(2)
PackageVulnerable rangeFix by version rangeDependents
python3.133.13.11-1 ... 3.13.9-1 (7 versions)
  • every version up to 3.13.14-1: fixed in 3.13.14-1
—
python3.143.14.0-1 ... 3.14.3-3 (17 versions)
  • every version up to 3.14.3-4: fixed in 3.14.3-4
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
python3—
  • every version up to 3.12.14-r0: fixed in 3.12.14-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
python3—
  • every version up to 3.12.14-r0: fixed in 3.12.14-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
python3—
  • every version up to 3.12.14-r0: fixed in 3.12.14-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
python3—
  • every version up to 3.14.5-r0: fixed in 3.14.5-r0
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
python3.113.11.2-6 ... 3.11.2-6+deb12u7 (8 versions)
  • every version up to 3.11.2-6+deb12u8: fixed in 3.11.2-6+deb12u8
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
python3.133.13.5-2, 3.13.5-2+deb13u1
  • every version up to 3.13.5-2+deb13u2: fixed in 3.13.5-2+deb13u2
—

Weakness Classification(1)

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 6× in last 7d / 21× 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 220 total refreshes for this CVE.

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

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

Frequently asked(5)

What is CVE-2026-4224?
CVE-2026-4224 is a high vulnerability published on March 16, 2026. When an Expat parser with a registered ElementDeclHandler parses an inline document type definition containing a deeply nested content model a C stack overflow occurs.
When was CVE-2026-4224 disclosed?
CVE-2026-4224 was first published on March 16, 2026, with the most recent update on August 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4224 actively exploited?
CVE-2026-4224 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (51st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-4224?
CVE-2026-4224 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-4224?
A fix for CVE-2026-4224 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-4224 are linked in the Vendor Advisories panel on this page.

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