CVE-2026-26199

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 78% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0

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

HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If H5Iget_name is invoked on a group id with 0 for the size parameter, it will underflow when trying to place a null terminator in the buffer. This can occur if H5Iget_name is invoked in a way where size can be forced to zero, and there is important data before the name buffer.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity65% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

July 20, 2026

Last Modified

July 29, 2026

Advisory Details (2)

Auto-updated Jul 20, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Buffer underflow in `H5Iget_name `/`H5G_get_name` if size is zero · Advisory · HDFGroup/hdf5 · GitHub

https://github.com/HDFGroup/hdf5/security/advisories/GHSA-5c6x-jmgf-f5vc
generic

hdf5/src/H5Gname.c at develop · HDFGroup/hdf5 · GitHub

https://github.com/HDFGroup/hdf5/blob/develop/src/H5Gname.c#L474

Vendor Advisories for CVE-2026-26199(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
hdf51.10.10+repack-1 ... 2.1.0+repack-1~exp9 (83 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
hdf51.10.10+repack-1 ... 2.2.0+repack-4 (76 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
hdf51.14.5+repack-3 ... 2.2.0+repack-4 (45 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
hdf51.14.5+repack-3 ... 2.2.0+repack-4 (45 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 64× 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 111 total refreshes for this CVE.

  1. 2026-09-11 14:52 UTCEPSS rescore
  2. 2026-09-11 09:29 UTCEG score recompute
  3. 2026-09-10 09:34 UTCEPSS rescore
  4. 2026-09-09 11:57 UTCEG score recompute
  5. 2026-09-09 11:57 UTCVendor advisory
  6. 2026-09-08 22:00 UTCEPSS rescore
  7. 2026-09-07 22:56 UTCEG score recompute
  8. 2026-09-07 22:56 UTCVendor advisory
  9. 2026-09-07 16:01 UTCEPSS rescore
  10. 2026-09-06 13:47 UTCEPSS rescore
  11. 2026-09-06 13:47 UTCEPSS rescore
  12. 2026-09-06 11:49 UTCEG score recompute
  13. 2026-09-06 11:49 UTCVendor advisory
  14. 2026-09-05 09:34 UTCEG score recompute
  15. 2026-09-05 09:34 UTCVendor advisory
  16. 2026-09-04 05:06 UTCEPSS rescore
  17. 2026-09-02 14:11 UTCEPSS rescore
  18. 2026-09-01 13:53 UTCEPSS rescore
  19. 2026-09-01 04:39 UTCEPSS rescore
  20. 2026-08-31 04:54 UTCEG score recompute
  21. 2026-08-31 04:54 UTCVendor advisory
  22. 2026-08-30 19:17 UTCEPSS rescore
  23. 2026-08-30 02:38 UTCEG score recompute
  24. 2026-08-30 02:38 UTCVendor advisory
  25. 2026-08-30 01:22 UTCEPSS rescore
Show 75 more
  1. 2026-08-28 21:41 UTCEPSS rescore
  2. 2026-08-27 14:25 UTCEPSS rescore
  3. 2026-08-27 05:01 UTCEG score recompute
  4. 2026-08-27 05:01 UTCVendor advisory
  5. 2026-08-26 14:46 UTCEPSS rescore
  6. 2026-08-26 01:59 UTCEG score recompute
  7. 2026-08-26 01:59 UTCVendor advisory
  8. 2026-08-25 13:48 UTCEPSS rescore
  9. 2026-08-24 23:43 UTCEG score recompute
  10. 2026-08-24 23:43 UTCVendor advisory
  11. 2026-08-23 21:27 UTCEG score recompute
  12. 2026-08-23 21:27 UTCVendor advisory
  13. 2026-08-23 00:19 UTCEPSS rescore
  14. 2026-08-22 19:11 UTCEG score recompute
  15. 2026-08-22 19:11 UTCVendor advisory
  16. 2026-08-21 23:49 UTCEPSS rescore
  17. 2026-08-21 16:55 UTCEG score recompute
  18. 2026-08-20 22:55 UTCEPSS rescore
  19. 2026-08-20 14:35 UTCEG score recompute
  20. 2026-08-20 14:35 UTCVendor advisory
  21. 2026-08-19 17:03 UTCEPSS rescore
  22. 2026-08-19 12:15 UTCEG score recompute
  23. 2026-08-19 12:15 UTCVendor advisory
  24. 2026-08-18 13:48 UTCEPSS rescore
  25. 2026-08-18 09:56 UTCEG score recompute
  26. 2026-08-17 13:47 UTCEPSS rescore
  27. 2026-08-17 07:40 UTCEG score recompute
  28. 2026-08-17 07:40 UTCVendor advisory
  29. 2026-08-16 14:56 UTCEPSS rescore
  30. 2026-08-16 05:24 UTCEG score recompute
  31. 2026-08-16 05:24 UTCVendor advisory
  32. 2026-08-16 02:14 UTCEPSS rescore
  33. 2026-08-15 03:09 UTCEG score recompute
  34. 2026-08-15 03:09 UTCVendor advisory
  35. 2026-08-15 01:30 UTCEPSS rescore
  36. 2026-08-14 00:53 UTCEG score recompute
  37. 2026-08-14 00:53 UTCVendor advisory
  38. 2026-08-13 22:00 UTCEPSS rescore
  39. 2026-08-12 22:37 UTCEG score recompute
  40. 2026-08-12 13:50 UTCEPSS rescore
  41. 2026-08-11 20:21 UTCEG score recompute
  42. 2026-08-11 20:21 UTCVendor advisory
  43. 2026-08-11 13:42 UTCEPSS rescore
  44. 2026-08-11 00:00 UTCEPSS rescore
  45. 2026-08-09 15:26 UTCEG score recompute
  46. 2026-08-09 13:46 UTCEPSS rescore
  47. 2026-08-08 16:37 UTCEPSS rescore
  48. 2026-08-08 13:11 UTCEG score recompute
  49. 2026-08-07 10:55 UTCEG score recompute
  50. 2026-08-06 13:46 UTCEPSS rescore
  51. 2026-08-06 08:39 UTCEG score recompute
  52. 2026-08-05 19:17 UTCEPSS rescore
  53. 2026-08-05 06:23 UTCEG score recompute
  54. 2026-08-04 15:10 UTCEPSS rescore
  55. 2026-08-04 04:06 UTCEG score recompute
  56. 2026-08-03 10:36 UTCEPSS rescore
  57. 2026-08-03 01:48 UTCEG score recompute
  58. 2026-08-02 02:26 UTCEPSS rescore
  59. 2026-08-01 23:32 UTCEG score recompute
  60. 2026-08-01 04:16 UTCEPSS rescore
  61. 2026-07-30 18:57 UTCEG score recompute
  62. 2026-07-30 16:27 UTCEPSS rescore
  63. 2026-07-30 01:30 UTCEPSS rescore
  64. 2026-07-29 15:43 UTCEG score recompute▲ 0.60
  65. 2026-07-29 15:41 UTCNVD updateCVSS v3 → 6.5
  66. 2026-07-29 11:22 UTCEG score recompute
  67. 2026-07-28 15:36 UTCEPSS rescore
  68. 2026-07-28 09:06 UTCEG score recompute
  69. 2026-07-27 06:47 UTCEG score recompute
  70. 2026-07-26 14:54 UTCEPSS rescore
  71. 2026-07-26 14:54 UTCEPSS rescore
  72. 2026-07-26 04:30 UTCEG score recompute
  73. 2026-07-25 14:18 UTCEPSS rescore
  74. 2026-07-25 14:17 UTCEPSS rescore
  75. 2026-07-24 14:17 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-26199?
CVE-2026-26199 is a medium vulnerability published on July 20, 2026. HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If H5Igetname is invoked on a group id with 0 for the size parameter, it will underflow when trying to place a null terminator in the buffer. This can occur if H5Igetname is invoked in a way…
When was CVE-2026-26199 disclosed?
CVE-2026-26199 was first published in the National Vulnerability Database on July 20, 2026, with the most recent update on July 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-26199 actively exploited?
CVE-2026-26199 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 77.9% of all scored CVEs.
What is the CVSS score of CVE-2026-26199?
CVE-2026-26199 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-26199?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-26199, 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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