CVE-2026-56409

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory published 2026-06-21. a secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0

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

xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is used.

CVSS v3
6.5
EG Score
6.5(high)
EPSS
1.0%
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-2026-56409] xmlwf: Protect output path join from integer overflow

Fix merged in libexpat/libexpat PR #1259 on 2026-06-01 — awaiting tagged release

https://github.com/libexpat/libexpat/pull/1259

Vendor Advisories for CVE-2026-56409(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 28× 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. 2026-07-06 21:30 UTCEG score recompute
  2. 2026-07-06 21:30 UTCVendor advisory
  3. 2026-07-06 21:30 UTCGHSA enrichment
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-05 20:53 UTCEG score recompute
  7. 2026-07-05 20:53 UTCVendor advisory
  8. 2026-07-05 20:53 UTCGHSA enrichment
  9. 2026-07-05 02:31 UTCEPSS rescore
  10. 2026-07-05 02:30 UTCEPSS rescore
  11. 2026-07-04 20:44 UTCEG score recompute
  12. 2026-07-04 20:44 UTCVendor advisory
  13. 2026-07-04 20:44 UTCGHSA enrichment
  14. 2026-07-04 06:31 UTCEPSS rescore
  15. 2026-07-04 06:31 UTCEPSS rescore
  16. 2026-07-03 20:36 UTCEG score recompute
  17. 2026-07-03 20:36 UTCVendor advisory
  18. 2026-07-03 20:35 UTCGHSA enrichment
  19. 2026-07-02 20:26 UTCEG score recompute
  20. 2026-07-02 20:26 UTCVendor advisory
  21. 2026-07-02 20:26 UTCGHSA enrichment
  22. 2026-07-01 20:18 UTCEG score recompute
  23. 2026-07-01 20:18 UTCVendor advisory
  24. 2026-07-01 20:18 UTCGHSA enrichment
  25. 2026-07-01 15:07 UTCEPSS rescore
Show 30 more
  1. 2026-06-30 20:10 UTCEG score recompute
  2. 2026-06-30 20:10 UTCVendor advisory
  3. 2026-06-30 20:10 UTCGHSA enrichment
  4. 2026-06-29 20:02 UTCEG score recompute
  5. 2026-06-29 20:02 UTCGHSA enrichment
  6. 2026-06-29 14:06 UTCEPSS rescore
  7. 2026-06-28 19:54 UTCEG score recompute
  8. 2026-06-28 19:54 UTCGHSA enrichment
  9. 2026-06-28 14:07 UTCEPSS rescore
  10. 2026-06-28 04:56 UTCEPSS rescore
  11. 2026-06-28 04:56 UTCEPSS rescore
  12. 2026-06-27 19:46 UTCEG score recompute
  13. 2026-06-27 19:46 UTCGHSA enrichment
  14. 2026-06-27 03:08 UTCEPSS rescore
  15. 2026-06-26 19:37 UTCEG score recompute
  16. 2026-06-26 19:37 UTCGHSA enrichment
  17. 2026-06-25 19:29 UTCEG score recompute
  18. 2026-06-25 19:29 UTCGHSA enrichment
  19. 2026-06-25 13:49 UTCEPSS rescore
  20. 2026-06-24 19:21 UTCEG score recompute
  21. 2026-06-24 19:21 UTCGHSA enrichment
  22. 2026-06-24 14:05 UTCEPSS rescore
  23. 2026-06-23 21:33 UTCEPSS rescore
  24. 2026-06-23 21:33 UTCEPSS rescore
  25. 2026-06-23 19:10 UTCEG score recompute
  26. 2026-06-23 19:09 UTCGHSA enrichment
  27. 2026-06-22 19:01 UTCEG score recompute
  28. 2026-06-22 19:01 UTCGHSA enrichment
  29. 2026-06-21 18:45 UTCEG score recompute
  30. 2026-06-21 18:45 UTCGHSA enrichment

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-56409?
CVE-2026-56409 is a medium vulnerability published on June 21, 2026. xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is used.
When was CVE-2026-56409 disclosed?
CVE-2026-56409 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-2026-56409 actively exploited?
CVE-2026-56409 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-56409?
CVE-2026-56409 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-56409?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56409, 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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