CVE-2026-56408

MEDIUMPre-NVD 6.96.9—
EchelonGraph scoreMEDIUM 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 — 3 sources updated this week
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

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 copyString.

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
3%
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_commit.
github_commit

commit 16e2efd867ea (libexpat/libexpat)

Fix landed in libexpat/libexpat commit 16e2efd867ea — awaiting tagged release

https://github.com/libexpat/libexpat/commit/16e2efd867ea8567ffa012210b52ef5918e20817

Vendor Advisories for CVE-2026-56408(1)

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 10× 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.

  1. 2026-07-29 01:25 UTCEG score recompute
  2. 2026-07-29 01:25 UTCGHSA enrichment
  3. 2026-07-28 15:37 UTCEPSS rescore
  4. 2026-07-27 17:59 UTCGHSA enrichment
  5. 2026-07-26 16:18 UTCEG score recompute
  6. 2026-07-26 16:18 UTCGHSA enrichment
  7. 2026-07-25 14:18 UTCEPSS rescore
  8. 2026-07-24 14:18 UTCEPSS rescore
  9. 2026-07-23 03:20 UTCEG score recompute
  10. 2026-07-22 14:08 UTCEPSS rescore
  11. 2026-07-20 17:08 UTCEPSS rescore
  12. 2026-07-19 14:31 UTCEPSS rescore
  13. 2026-07-19 14:31 UTCEPSS rescore
  14. 2026-07-19 02:29 UTCEPSS rescore
  15. 2026-07-18 10:04 UTCEPSS rescore
  16. 2026-07-16 17:03 UTCEPSS rescore
  17. 2026-07-16 09:01 UTCGHSA enrichment
  18. 2026-07-15 16:57 UTCEPSS rescore
  19. 2026-07-15 16:57 UTCEPSS rescore
  20. 2026-07-15 09:27 UTCGHSA enrichment
  21. 2026-07-15 02:00 UTCEPSS rescore
  22. 2026-07-15 02:00 UTCEPSS rescore
  23. 2026-07-14 09:52 UTCGHSA enrichment
  24. 2026-07-13 22:31 UTCEPSS rescore
  25. 2026-07-13 10:18 UTCGHSA enrichment
Show 47 more
  1. 2026-07-12 10:40 UTCGHSA enrichment
  2. 2026-07-12 05:46 UTCEPSS rescore
  3. 2026-07-11 11:00 UTCGHSA enrichment
  4. 2026-07-11 08:27 UTCEPSS rescore
  5. 2026-07-11 08:27 UTCEPSS rescore
  6. 2026-07-10 11:26 UTCGHSA enrichment
  7. 2026-07-09 19:10 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-09 11:50 UTCGHSA enrichment
  10. 2026-07-08 12:17 UTCGHSA enrichment
  11. 2026-07-07 13:46 UTCEPSS rescore
  12. 2026-07-07 13:46 UTCEPSS rescore
  13. 2026-07-07 12:10 UTCGHSA enrichment
  14. 2026-07-06 16:27 UTCEPSS rescore
  15. 2026-07-06 16:27 UTCEPSS rescore
  16. 2026-07-06 12:34 UTCGHSA enrichment
  17. 2026-07-05 13:01 UTCGHSA enrichment
  18. 2026-07-05 02:31 UTCEPSS rescore
  19. 2026-07-05 02:30 UTCEPSS rescore
  20. 2026-07-04 13:28 UTCGHSA enrichment
  21. 2026-07-04 06:31 UTCEPSS rescore
  22. 2026-07-04 06:31 UTCEPSS rescore
  23. 2026-07-03 13:54 UTCGHSA enrichment
  24. 2026-07-02 14:21 UTCGHSA enrichment
  25. 2026-07-01 15:07 UTCEPSS rescore
  26. 2026-07-01 14:49 UTCGHSA enrichment
  27. 2026-06-30 23:22 UTCEPSS rescore
  28. 2026-06-30 15:15 UTCGHSA enrichment
  29. 2026-06-29 15:39 UTCGHSA enrichment
  30. 2026-06-29 14:06 UTCEPSS rescore
  31. 2026-06-28 16:06 UTCGHSA enrichment
  32. 2026-06-28 14:07 UTCEPSS rescore
  33. 2026-06-28 04:56 UTCEPSS rescore
  34. 2026-06-28 04:56 UTCEPSS rescore
  35. 2026-06-27 16:31 UTCGHSA enrichment
  36. 2026-06-27 03:08 UTCEPSS rescore
  37. 2026-06-26 16:54 UTCGHSA enrichment
  38. 2026-06-25 17:21 UTCGHSA enrichment
  39. 2026-06-25 13:49 UTCEPSS rescore
  40. 2026-06-24 17:48 UTCGHSA enrichment
  41. 2026-06-24 14:05 UTCEPSS rescore
  42. 2026-06-23 21:33 UTCEPSS rescore
  43. 2026-06-23 21:33 UTCEPSS rescore
  44. 2026-06-23 17:56 UTCGHSA enrichment
  45. 2026-06-22 18:19 UTCGHSA enrichment
  46. 2026-06-21 18:45 UTCEG score recompute
  47. 2026-06-21 18:45 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-56408?
CVE-2026-56408 is a medium vulnerability published on June 21, 2026. libexpat before 2.8.2 has an integer overflow in copyString.
When was CVE-2026-56408 disclosed?
CVE-2026-56408 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-2026-56408 actively exploited?
CVE-2026-56408 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 97.4% of all scored CVEs.
What is the CVSS score of CVE-2026-56408?
CVE-2026-56408 has a CVSS v3 base score of 6.9 (NVD).
How do I remediate CVE-2026-56408?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56408, 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-2026-56408

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