CVE-2026-56131

MEDIUMPre-NVD 4.94.9—
EchelonGraph scoreMEDIUM confidence

Score 4.9 from GitHub Security Advisory published 2026-06-19. a secondary CVSS source baseline 4.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
4.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.9Exploit: None knownExposed: 0

A fix is available — apply it.

libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation).

CVSS v3
4.9
EG Score
4.9(medium)
EG Risk
27(Track)
EG Risk 27/100SSVC: 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
Severity49% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
8%
KEV
Not listed

Published

June 19, 2026

Last Modified

June 23, 2026

Advisory Details (1)

Auto-updated Jun 22, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
github_pr

[CVE-2026-56131] lib: Protect `XML_ResumeParser` from being called from a handler

Fix merged in libexpat/libexpat PR #1267 on 2026-06-20 — awaiting tagged release

https://github.com/libexpat/libexpat/pull/1267

Vendor Advisories for CVE-2026-56131(3)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatexpat-main-2.8.2-1.1.hum12026-07-15redhat

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

(8 across 8 ecosystems)
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
expat—2.8.2-r0—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
expat—2.8.2-r0—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
expat—2.8.2-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
expat—2.8.2-r0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
expat2.2.10-2 ... 2.8.2-1~deb13u1 (47 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
expat2.5.0-1, 2.5.0-1+deb12u1, 2.5.0-1+deb12u22.5.0-1+deb12u3—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
expat2.7.1-2 ... 2.8.1-1 (9 versions)2.8.2-1~deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
expat2.7.1-2 ... 2.8.2-1~deb13u1 (10 versions)2.8.2-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 60× 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 203 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-56131?
CVE-2026-56131 is a medium vulnerability published on June 19, 2026. libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation).
When was CVE-2026-56131 disclosed?
CVE-2026-56131 was first published in the National Vulnerability Database on June 19, 2026, with the most recent update on June 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56131 actively exploited?
CVE-2026-56131 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 92.1% of all scored CVEs.
What is the CVSS score of CVE-2026-56131?
CVE-2026-56131 has a CVSS v3 base score of 4.9 (NVD).
How do I remediate CVE-2026-56131?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56131, 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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