CVE-2026-120756

MEDIUMNVD 6.16.1
EchelonGraph scoreHIGH confidence

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

Score 6.1 from GitHub Security Advisory (severity: LOW) published 2026-11-03. NVD baseline CVSS 6.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2026-116008 (ENISA EUVD) · GHSA-m9xj-6f2h-rx5r (GitHub Security Advisories)Source: ENISA EUVD

6.1EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

HDF5 through 2.2.0 contains a heap buffer over-read vulnerability in H5O__chunk_deserialize() in src/H5Ocache.c. When decoding object header messages, the declared message size is checked against the end of the chunk image before the remainder of the message header (flags, and for version 2 object headers, the optional creation index) has been decoded. Because the message body begins after these fields, a message can start up to four bytes further into the chunk than the size check accounts for. A crafted HDF5 file can declare a message size that passes the check but extends past the end of the chunk image, causing the message’s decode callback, for example H5O__mtime_new_decode() in src/H5Omtime.c, to read beyond the heap allocation. The flaw is reachable during H5Fopen() on a crafted file. An attacker who can get a user or application to open a malicious file can cause a denial of service or limited disclosure of process memory.

CVSS v3
6.1
EG Score
6.1MEDIUMhigh confidence
EG Risk
28
EG Risk 28/100

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)
Severity61% × 45%
Impact severity (EG Severity): CVSS 6.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (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
7th
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 (6.1): severity, escalated by confirmed exploitation. This CVE's 6.1 is its impact severity (EG Severity), not escalated.

EG Severity
6.1 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-10). 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 every mission impact level.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 every mission impact level.

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

Exploitation none (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

November 3, 2026

Last Modified

November 3, 2026

References (2)

Vendor Advisories for CVE-2026-120756(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-2.2.0-0.1.5.hum12026-11-04redhat

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

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
hdf51.10.10+repack-1 ... 2.2.0+repack-6 (78 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-6 (47 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-6 (47 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 9× in last 7d / 16× 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 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). "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.

  1. 2026-11-13 16:50 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  2. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  3. 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  4. 2026-11-11 07:03 UTCEchelonGraph re-scored
  5. 2026-11-11 07:03 UTCVendor advisory
  6. 2026-11-11 07:03 UTCGHSA enrichmentGHSA-m9xj-6f2h-rx5r · GitHub severity LOW · GitHub CVSS 6.1
  7. 2026-11-10 16:42 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  8. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  9. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  10. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  11. 2026-11-06 16:36 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  12. 2026-11-05 16:36 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  13. 2026-11-04 16:34 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  14. 2026-11-03 21:30 UTCEchelonGraph re-scored▲ 4.20
  15. 2026-11-03 21:30 UTCGHSA enrichmentGHSA-m9xj-6f2h-rx5r · GitHub severity LOW
  16. 2026-11-03 21:26 UTCNVD updateCVSS v3 → 6.1 · severity → MEDIUM
  17. 2026-11-03 18:29 UTCEchelonGraph re-scored
  18. 2026-11-03 17:03 UTCENISA EUVD ID recordedEUVD-2026-116008 · Source: ENISA EUVD
  19. 2026-11-03 16:31 UTCEchelonGraph re-scored
  20. 2026-11-03 15:42 UTCEchelonGraph re-scoredFirst assessed: 1.9 LOW
  21. 2026-11-03 15:41 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same vendor + same CWE)

Same vendor

2 shown

redhat:RHSA-2026:94898

Frequently asked(5)

What is CVE-2026-120756?
CVE-2026-120756 is a medium-severity vulnerability; its CVE record was published on November 3, 2026. HDF5 through 2.2.0 contains a heap buffer over-read vulnerability in H5O__chunk_deserialize() in src/H5Ocache.c. When decoding object header messages, the declared message size is checked against the end of the chunk image before the remainder of the message header (flags, and for version 2 object…
When was the CVE record for CVE-2026-120756 published?
The CVE record for CVE-2026-120756 was published on November 3, 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 November 3, 2026; the record at its source may have been updated since.
Is CVE-2026-120756 actively exploited?
CVE-2026-120756 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (7th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-120756?
CVE-2026-120756 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-120756?
A fix for CVE-2026-120756 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-120756 are linked in the Vendor Advisories panel on this page.

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