CVE-2026-19028

MEDIUMPre-NVD 6.86.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 6.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (9th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated

Also known asEUVD-2026-53676 (ENISA EUVD) · GHSA-2hg9-348w-39gj (GitHub Security Advisories)Source: ENISA EUVD

6.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.8Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

H5Z__filter_fletcher32 in H5Zfletcher32.c in HDF5 prior to 2.3.0 computes the data length to checksum by subtracting the 4-byte trailing checksum size from the input buffer size without checking that the buffer is at least 4 bytes, allowing a size_t underflow. This allows attackers to cause a denial of service (massively out-of-bounds read and application crash in H5_checksum_fletcher32) via a crafted HDF5 file with a Fletcher32-filtered chunk smaller than 4 bytes, triggered via H5Dread, e.g. by the h5ls or h5dump tools.

CVSS
6.8
EG Score
6.8MEDIUMmedium confidence
EG Risk
47
EG Risk 47/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity68% × 45%
Impact severity (EG Severity): CVSS 6.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
9th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.8): severity, escalated by confirmed exploitation. This CVE's 6.8 is its impact severity (EG Severity), not escalated.

EG Severity
6.8 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-07). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track 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). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 5, 2026

Last Modified

October 23, 2026

Advisory Details (3)

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

h5ls: SIGSEGV in H5_checksum_fletcher32 due to underflowed checksum length · Issue #6490 · HDFGroup/hdf5 · GitHub

https://github.com/HDFGroup/hdf5/issues/6490
Web page

h5dump: SIGSEGV in H5_checksum_fletcher32 due to underflowed checksum length · Issue #6488 · HDFGroup/hdf5 · GitHub

https://github.com/HDFGroup/hdf5/issues/6488
GitHub pull request

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-2026-19028(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(3)

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 7× in last 7d / 35× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 222 rows on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 122 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  2. 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  3. 2026-11-10 16:42 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  4. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  5. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  6. 2026-11-07 19:43 UTCGHSA enrichmentGHSA-2hg9-348w-39gj · GitHub severity MODERATE
  7. 2026-11-07 19:43 UTCEchelonGraph re-scored
  8. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  9. 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  10. 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  11. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  12. 2026-11-03 16:47 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  13. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  14. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  15. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  16. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  17. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  18. 2026-10-29 16:01 UTCEchelonGraph re-scored
  19. 2026-10-29 16:01 UTCVendor advisory
  20. 2026-10-29 16:01 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  21. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  22. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  23. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  24. 2026-10-25 14:44 UTCEchelonGraph re-scored
  25. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
Show 75 more
  1. 2026-10-23 21:33 UTCEchelonGraph re-scored
  2. 2026-10-23 21:33 UTCVendor advisory
  3. 2026-10-23 21:33 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  4. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  5. 2026-10-23 05:57 UTCEchelonGraph re-scored
  6. 2026-10-23 05:57 UTCVendor advisory
  7. 2026-10-23 05:56 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  8. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  9. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  10. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  11. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  12. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  13. 2026-10-18 03:58 UTCEchelonGraph re-scored
  14. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  15. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  16. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  17. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  18. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  19. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  20. 2026-10-12 16:26 UTCEchelonGraph re-scored
  21. 2026-10-11 20:07 UTCEchelonGraph re-scored
  22. 2026-10-11 17:19 UTCEchelonGraph re-scored
  23. 2026-10-11 14:52 UTCEchelonGraph re-scored
  24. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  25. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  26. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  27. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  28. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  29. 2026-10-06 21:33 UTCEchelonGraph re-scored
  30. 2026-10-06 21:33 UTCVendor advisory
  31. 2026-10-06 21:33 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  32. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  33. 2026-10-05 19:32 UTCEchelonGraph re-scored
  34. 2026-10-05 19:32 UTCVendor advisory
  35. 2026-10-05 19:32 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  36. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  37. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  38. 2026-10-04 05:57 UTCEchelonGraph re-scored
  39. 2026-10-04 05:57 UTCVendor advisory
  40. 2026-10-04 05:57 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  41. 2026-10-02 09:50 UTCEchelonGraph re-scored
  42. 2026-10-02 09:50 UTCVendor advisory
  43. 2026-10-02 09:50 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  44. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  45. 2026-10-01 01:51 UTCEchelonGraph re-scored
  46. 2026-10-01 01:51 UTCVendor advisory
  47. 2026-10-01 01:51 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  48. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  49. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  50. 2026-09-29 06:07 UTCEchelonGraph re-scored
  51. 2026-09-29 06:07 UTCVendor advisory
  52. 2026-09-29 06:07 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  53. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  54. 2026-09-27 17:38 UTCEchelonGraph re-scored
  55. 2026-09-27 17:38 UTCVendor advisory
  56. 2026-09-27 17:38 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  57. 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  58. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  59. 2026-09-25 04:29 UTCEchelonGraph re-scored
  60. 2026-09-25 04:29 UTCVendor advisory
  61. 2026-09-25 04:29 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  62. 2026-09-23 16:11 UTCEchelonGraph re-scored
  63. 2026-09-23 16:11 UTCVendor advisory
  64. 2026-09-23 16:11 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  65. 2026-09-22 15:00 UTCEchelonGraph re-scored
  66. 2026-09-22 15:00 UTCVendor advisory
  67. 2026-09-22 15:00 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  68. 2026-09-21 13:03 UTCEchelonGraph re-scored
  69. 2026-09-21 13:03 UTCVendor advisory
  70. 2026-09-21 13:03 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  71. 2026-09-20 04:12 UTCEchelonGraph re-scored
  72. 2026-09-20 04:12 UTCVendor advisory
  73. 2026-09-20 04:12 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  74. 2026-09-19 03:17 UTCEchelonGraph re-scored
  75. 2026-09-19 03:17 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-19028?
CVE-2026-19028 is a medium-severity vulnerability; its CVE record was published on August 5, 2026. H5Z__filter_fletcher32 in H5Zfletcher32.c in HDF5 prior to 2.3.0 computes the data length to checksum by subtracting the 4-byte trailing checksum size from the input buffer size without checking that the buffer is at least 4 bytes, allowing a size_t underflow. This allows attackers to cause a…
When was the CVE record for CVE-2026-19028 published?
The CVE record for CVE-2026-19028 was published on August 5, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 23, 2026; the record at its source may have been updated since.
Is CVE-2026-19028 actively exploited?
CVE-2026-19028 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (9th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-19028?
CVE-2026-19028 has a CVSS base score of 6.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-19028?
A fix for CVE-2026-19028 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-19028 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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