CVE-2026-26199

MEDIUMNVD 6.56.5
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.4% (28th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Trending — 3 sources updated this weekElevated

Also known asEUVD-2026-45970 (ENISA EUVD)Source: ENISA EUVD

6.5EG
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: 0.4%CVSS: 6.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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
6.5MEDIUMmedium confidence
EG Risk
45
EG Risk 45/100

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)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 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
0.4%
EPSS %ILE
28th
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 (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.4% 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: 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.

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

July 20, 2026

Last Modified

October 24, 2026

Advisory Details (2)

Auto-updated Jul 20, 2026
Patch available. Sources: github.
GitHub advisoryMentions a patch (unverified)

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
Web page

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 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.

Data Freshness Timeline

(refreshed 11× in last 7d / 44× 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 97 of 178 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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 81 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  2. 2026-10-29 16:11 UTCEG score recompute
  3. 2026-10-29 16:11 UTCVendor advisory
  4. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  5. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  6. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  7. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  8. 2026-10-25 14:39 UTCEG score recompute
  9. 2026-10-24 20:28 UTCEG score recompute
  10. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  11. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  12. 2026-10-23 04:28 UTCEG score recompute
  13. 2026-10-23 04:28 UTCVendor advisory
  14. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  15. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  16. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  17. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  18. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  19. 2026-10-18 03:52 UTCEG score recompute
  20. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  21. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  22. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  23. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  24. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  25. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.4% · 26th percentile
Show 72 more
  1. 2026-10-12 16:18 UTCEG score recompute
  2. 2026-10-11 20:00 UTCEG score recompute
  3. 2026-10-11 17:14 UTCEG score recompute
  4. 2026-10-11 14:45 UTCEG score recompute
  5. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  6. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  7. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  8. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  9. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  10. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  11. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  12. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  13. 2026-10-04 14:56 UTCEG score recompute
  14. 2026-10-04 14:56 UTCVendor advisory
  15. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  16. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  17. 2026-10-01 07:45 UTCEG score recompute
  18. 2026-10-01 07:45 UTCVendor advisory
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  20. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  21. 2026-09-28 06:23 UTCEG score recompute
  22. 2026-09-28 06:23 UTCVendor advisory
  23. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  24. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  25. 2026-09-24 04:11 UTCEG score recompute
  26. 2026-09-24 04:11 UTCVendor advisory
  27. 2026-09-23 01:43 UTCEG score recompute
  28. 2026-09-23 01:43 UTCVendor advisory
  29. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  30. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  31. 2026-09-18 03:58 UTCEG score recompute
  32. 2026-09-18 03:58 UTCVendor advisory
  33. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  34. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  35. 2026-09-16 12:48 UTCEG score recompute
  36. 2026-09-16 12:48 UTCVendor advisory
  37. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  38. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  39. 2026-09-13 16:01 UTCEG score recompute
  40. 2026-09-13 16:01 UTCVendor advisory
  41. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  42. 2026-09-12 12:34 UTCEG score recompute
  43. 2026-09-12 12:34 UTCVendor advisory
  44. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  45. 2026-09-11 09:29 UTCEG score recompute
  46. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  47. 2026-09-09 11:57 UTCEG score recompute
  48. 2026-09-09 11:57 UTCVendor advisory
  49. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  50. 2026-09-07 22:56 UTCEG score recompute
  51. 2026-09-07 22:56 UTCVendor advisory
  52. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  53. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  54. 2026-09-06 11:49 UTCEG score recompute
  55. 2026-09-06 11:49 UTCVendor advisory
  56. 2026-09-05 09:34 UTCEG score recompute
  57. 2026-09-05 09:34 UTCVendor advisory
  58. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  59. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  60. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  61. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  62. 2026-08-31 04:54 UTCEG score recompute
  63. 2026-08-31 04:54 UTCVendor advisory
  64. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  65. 2026-08-30 02:38 UTCEG score recompute
  66. 2026-08-30 02:38 UTCVendor advisory
  67. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  68. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  69. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  70. 2026-08-27 05:01 UTCEG score recompute
  71. 2026-08-27 05:01 UTCVendor advisory
  72. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 21st percentile

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-26199?
CVE-2026-26199 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-26199 published?
The CVE record for CVE-2026-26199 was published on July 20, 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 24, 2026; the record at its source may have been updated since.
Is CVE-2026-26199 actively exploited?
CVE-2026-26199 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (28th percentile of EPSS-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?
A fix for CVE-2026-26199 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-26199 are linked in the Vendor Advisories panel on this page.

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