CVE-2026-19027

MEDIUMPre-NVD 6.96.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (6th percentile of EPSS-scored CVEs). 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, secondary
Trending — Patch released this weekElevated
6.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.9Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

The H5Z__nbit_decompress_one_byte, H5Z__nbit_decompress_one_nooptype, and H5Z__nbit_decompress_one_atomic functions in H5Znbit.c in HDF5 through 2.3.0 advance a read index into the compressed chunk buffer without bounding it against the buffer's actual size. This allows attackers to cause an out-of-bounds heap read, and in constrained cases disclosure of adjacent heap memory into decompressed dataset values, via a crafted HDF5 file whose N-Bit filter parameters describe more decompressed data than the stored compressed chunk actually contains, triggered via H5Dread, e.g. by the h5ls or h5repack tools.

CVSS v3
6.9
EG Score
6.9MEDIUMmedium confidence
EG Risk
47
EG Risk 47/100CISA SSVC

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%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
6th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 5, 2026

Last Modified

August 31, 2026

Advisory Details (3)

Auto-updated Aug 5, 2026
Patch available. Sources: github_pr.
generic

Issue · GitHub

https://github.com/HDFGroup/hdf5/issues/6492
generic

h5ls: SIGSEGV in Nbit filter processing when dumping datasets · Issue #6489 · HDFGroup/hdf5 · GitHub

https://github.com/HDFGroup/hdf5/issues/6489
github_pr

Fix h5ls SIGSEGVs in Nbit and Fletcher32 filter decode paths

Upstream fix in progress (PR #6497 · HDFGroup/hdf5, state=open)

https://github.com/HDFGroup/hdf5/pull/6497

Vendor Advisories for CVE-2026-19027(2)

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 / EcosystemFix (by version range) / PatchReleasedSource
redhathdf5-main-2.2.0-0.1.2.hum12026-09-29redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
hdf51.10.10+repack-1 ... 2.1.0+repack-1~exp9 (83 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
hdf51.10.10+repack-1 ... 2.2.0+repack-5 (77 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
hdf51.14.5+repack-3 ... 2.2.0+repack-5 (46 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
hdf51.14.5+repack-3 ... 2.2.0+repack-5 (46 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 17× in last 7d / 77× 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 162 total refreshes for this CVE.

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

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redhat:RHSA-2026:73539

Frequently asked(5)

What is CVE-2026-19027?
CVE-2026-19027 is a medium vulnerability published on August 5, 2026. The H5Znbitdecompressonebyte, H5Znbitdecompressonenooptype, and H5Znbitdecompressone_atomic functions in H5Znbit.c in HDF5 through 2.3.0 advance a read index into the compressed chunk buffer without bounding it against the buffer's actual size. This allows attackers to cause an out-of-bounds heap…
When was CVE-2026-19027 disclosed?
CVE-2026-19027 was first published on August 5, 2026, with the most recent update on August 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-19027 actively exploited?
CVE-2026-19027 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (6th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-19027?
CVE-2026-19027 has a CVSS base score of 6.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-19027?
A fix for CVE-2026-19027 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-19027 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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