CVE-2026-56407

MEDIUMPre-NVD 6.96.9—
EchelonGraph scoreHIGH confidence

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

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
6.9
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.9Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.

CVSS v3
6.9
EG Score
6.9(high)
EPSS
1.1%
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-2026-56407] Cap entity `textLen` against signed integer overflow

Fix merged in libexpat/libexpat PR #1262 on 2026-06-03 — awaiting tagged release

https://github.com/libexpat/libexpat/pull/1262

Vendor Advisories for CVE-2026-56407(2)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 32× in last 7d / 58× 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.

  1. 2026-07-07 05:26 UTCEG score recompute
  2. 2026-07-07 05:26 UTCVendor advisory
  3. 2026-07-07 05:26 UTCGHSA enrichment
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 06:19 UTCEG score recompute
  7. 2026-07-06 06:19 UTCVendor advisory
  8. 2026-07-06 06:19 UTCGHSA enrichment
  9. 2026-07-05 06:55 UTCEG score recompute
  10. 2026-07-05 06:55 UTCVendor advisory
  11. 2026-07-05 06:54 UTCGHSA enrichment
  12. 2026-07-05 02:31 UTCEPSS rescore
  13. 2026-07-05 02:30 UTCEPSS rescore
  14. 2026-07-04 07:47 UTCEG score recompute
  15. 2026-07-04 07:47 UTCVendor advisory
  16. 2026-07-04 07:47 UTCGHSA enrichment
  17. 2026-07-04 06:31 UTCEPSS rescore
  18. 2026-07-04 06:31 UTCEPSS rescore
  19. 2026-07-03 08:04 UTCEG score recompute
  20. 2026-07-03 08:04 UTCVendor advisory
  21. 2026-07-03 08:04 UTCGHSA enrichment
  22. 2026-07-02 08:57 UTCEG score recompute
  23. 2026-07-02 08:57 UTCVendor advisory
  24. 2026-07-02 08:57 UTCGHSA enrichment
  25. 2026-07-01 15:07 UTCEPSS rescore
Show 33 more
  1. 2026-07-01 09:50 UTCEG score recompute
  2. 2026-07-01 09:50 UTCVendor advisory
  3. 2026-07-01 09:49 UTCGHSA enrichment
  4. 2026-06-30 23:22 UTCEPSS rescore
  5. 2026-06-30 10:40 UTCEG score recompute
  6. 2026-06-30 10:40 UTCVendor advisory
  7. 2026-06-30 10:40 UTCGHSA enrichment
  8. 2026-06-29 11:33 UTCEG score recompute
  9. 2026-06-29 11:33 UTCGHSA enrichment
  10. 2026-06-28 14:07 UTCEPSS rescore
  11. 2026-06-28 12:28 UTCEG score recompute
  12. 2026-06-28 12:28 UTCGHSA enrichment
  13. 2026-06-28 04:56 UTCEPSS rescore
  14. 2026-06-28 04:56 UTCEPSS rescore
  15. 2026-06-27 13:23 UTCEG score recompute
  16. 2026-06-27 13:23 UTCGHSA enrichment
  17. 2026-06-27 03:08 UTCEPSS rescore
  18. 2026-06-26 14:19 UTCEG score recompute
  19. 2026-06-26 14:19 UTCGHSA enrichment
  20. 2026-06-25 15:14 UTCEG score recompute
  21. 2026-06-25 15:14 UTCGHSA enrichment
  22. 2026-06-25 13:49 UTCEPSS rescore
  23. 2026-06-24 16:08 UTCEG score recompute
  24. 2026-06-24 16:08 UTCGHSA enrichment
  25. 2026-06-24 14:05 UTCEPSS rescore
  26. 2026-06-23 21:33 UTCEPSS rescore
  27. 2026-06-23 21:33 UTCEPSS rescore
  28. 2026-06-23 17:03 UTCEG score recompute
  29. 2026-06-23 17:03 UTCGHSA enrichment
  30. 2026-06-22 17:57 UTCEG score recompute
  31. 2026-06-22 17:57 UTCGHSA enrichment
  32. 2026-06-21 18:46 UTCEG score recompute
  33. 2026-06-21 18:45 UTCGHSA enrichment

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-56407?
CVE-2026-56407 is a medium vulnerability published on June 21, 2026. libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.
When was CVE-2026-56407 disclosed?
CVE-2026-56407 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-2026-56407 actively exploited?
CVE-2026-56407 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-56407?
CVE-2026-56407 has a CVSS v3 base score of 6.9 (NVD).
How do I remediate CVE-2026-56407?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56407, 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

Explore the affected products and dependency analysis for CVE-2026-56407

Explore →

Is Your Infrastructure Affected by CVE-2026-56407?

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

Start Free Scan →Browse All CVEs