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
Trending — 4 sources updated this weekElevated

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 v3
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 · CVSS v3.0 or v3.1
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-28). 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 10× in last 7d / 53× 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 it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 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). Most recent first.

Showing the most recent 100 of 210 refreshes 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 110 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  2. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  3. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  4. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  5. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  6. 2026-10-29 16:01 UTCEG score recompute
  7. 2026-10-29 16:01 UTCVendor advisory
  8. 2026-10-29 16:01 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  9. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  10. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  11. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  12. 2026-10-25 14:44 UTCEG score recompute
  13. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  14. 2026-10-23 21:33 UTCEG score recompute
  15. 2026-10-23 21:33 UTCVendor advisory
  16. 2026-10-23 21:33 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  17. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  18. 2026-10-23 05:57 UTCEG score recompute
  19. 2026-10-23 05:57 UTCVendor advisory
  20. 2026-10-23 05:56 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  21. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  22. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  23. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  24. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  25. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
Show 75 more
  1. 2026-10-18 03:58 UTCEG score recompute
  2. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  3. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  4. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  5. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  6. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  7. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  8. 2026-10-12 16:26 UTCEG score recompute
  9. 2026-10-11 20:07 UTCEG score recompute
  10. 2026-10-11 17:19 UTCEG score recompute
  11. 2026-10-11 14:52 UTCEG score recompute
  12. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  13. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  14. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  15. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  16. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  17. 2026-10-06 21:33 UTCEG score recompute
  18. 2026-10-06 21:33 UTCVendor advisory
  19. 2026-10-06 21:33 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  20. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  21. 2026-10-05 19:32 UTCEG score recompute
  22. 2026-10-05 19:32 UTCVendor advisory
  23. 2026-10-05 19:32 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  24. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  25. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  26. 2026-10-04 05:57 UTCEG score recompute
  27. 2026-10-04 05:57 UTCVendor advisory
  28. 2026-10-04 05:57 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  29. 2026-10-02 09:50 UTCEG score recompute
  30. 2026-10-02 09:50 UTCVendor advisory
  31. 2026-10-02 09:50 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  32. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  33. 2026-10-01 01:51 UTCEG score recompute
  34. 2026-10-01 01:51 UTCVendor advisory
  35. 2026-10-01 01:51 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  36. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  37. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  38. 2026-09-29 06:07 UTCEG score recompute
  39. 2026-09-29 06:07 UTCVendor advisory
  40. 2026-09-29 06:07 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  41. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  42. 2026-09-27 17:38 UTCEG score recompute
  43. 2026-09-27 17:38 UTCVendor advisory
  44. 2026-09-27 17:38 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  45. 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  46. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  47. 2026-09-25 04:29 UTCEG score recompute
  48. 2026-09-25 04:29 UTCVendor advisory
  49. 2026-09-25 04:29 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  50. 2026-09-23 16:11 UTCEG score recompute
  51. 2026-09-23 16:11 UTCVendor advisory
  52. 2026-09-23 16:11 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  53. 2026-09-22 15:00 UTCEG score recompute
  54. 2026-09-22 15:00 UTCVendor advisory
  55. 2026-09-22 15:00 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  56. 2026-09-21 13:03 UTCEG score recompute
  57. 2026-09-21 13:03 UTCVendor advisory
  58. 2026-09-21 13:03 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  59. 2026-09-20 04:12 UTCEG score recompute
  60. 2026-09-20 04:12 UTCVendor advisory
  61. 2026-09-20 04:12 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  62. 2026-09-19 03:17 UTCEG score recompute
  63. 2026-09-19 03:17 UTCVendor advisory
  64. 2026-09-19 03:17 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  65. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  66. 2026-09-18 01:59 UTCEG score recompute
  67. 2026-09-18 01:59 UTCVendor advisory
  68. 2026-09-18 01:59 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  69. 2026-09-17 01:04 UTCEG score recompute
  70. 2026-09-17 01:04 UTCVendor advisory
  71. 2026-09-17 01:04 UTCGHSA enrichmentGHSA-2hg9-348w-39gj
  72. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  73. 2026-09-16 05:14 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  74. 2026-09-15 16:08 UTCEG score recompute
  75. 2026-09-15 16:08 UTCVendor advisory

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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.

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