CVE-2026-56404

MEDIUMNVD 6.96.9—
EchelonGraph scoreMEDIUM confidence

Score 6.9 from GitHub Security Advisory published 2026-06-21. NVD baseline CVSS 6.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.9Exploit: None knownExposed: 0

A fix is available — apply it.

libexpat before 2.8.2 has an integer overflow in addBinding.

CVSS v3
6.9
EG Score
6.9(medium)
EG Risk
36(Track)
EG Risk 36/100SSVC: 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
Severity69% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

June 21, 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-2026-56404] lib: Protect function `addBinding` from signed integer overflow

Fix merged in libexpat/libexpat PR #1249 on 2026-05-29 — awaiting tagged release

https://github.com/libexpat/libexpat/pull/1249

Vendor Advisories for CVE-2026-56404(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 4× in last 7d / 55× 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 190 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-56404?
CVE-2026-56404 is a medium vulnerability published on June 21, 2026. libexpat before 2.8.2 has an integer overflow in addBinding.
When was CVE-2026-56404 disclosed?
CVE-2026-56404 was first published in the National Vulnerability Database on June 21, 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-2026-56404 actively exploited?
CVE-2026-56404 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 96.3% of all scored CVEs.
What is the CVSS score of CVE-2026-56404?
CVE-2026-56404 has a CVSS v3 base score of 6.9 (NVD).
How do I remediate CVE-2026-56404?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56404, 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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