CVE-2026-26199

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.35% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 28.5% of scored records. A rank, not a probability.

NVD base score

5.9 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Analyzed. NVD last modified this record on 2026-10-24.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-07-20 14:59Z3 MO AGO

Last updated

2026-07-20 18:56Z3 MO AGO

Reserved

2026-02-11

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

Medium (CVSS 5.9)

CNA CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Weaknesses

• CWE-124Buffer Underwrite ('Buffer Underflow')Base

Data version

5.2

Document digest

596308668c50a507f03b934f84a69e635b3d2dd67e1b094fe0113ac8d7a027ec

• github.comhttps://github.com/HDFGroup/hdf5/security/advisories/GHSA-5c6x-jmgf-f5vcx_refsource_CONFIRM
• github.comhttps://github.com/HDFGroup/hdf5/blob/develop/src/H5Gname.c#L474x_refsource_MISC