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Fencer Vulns
high 7.5

CVE-2026-26197 json

Array full size, element count, and element size are not checked to make sure they match in H5Odtype.c

published 2026-07-20 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-45969 , JLSEC-2026-1162

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If a file is corrupted such that an array datatype's size, the number of elements, and the element size are not in agreement it can trigger an out of bounds read. The array datatype stores the full size of the datatype (`dt->shared->size`) separately from the number of elements (`dt->shared->u.array.nelem`) and the element size (`dt->shared->parent->shared->size`). If any one of these are corrupted so that they don't align with the others (element size * nelem = full size), it can lead to an out of bounds read. Depending on what is corrupted, it can alter the type of out of bounds read triggered. The vulnerability is present only in files that have been maliciously altered, as its generally not possible to independently alter the full size of the datatype, the element count and the element size. As such, this is only present if a malicious actor is altering files, and won't appear in regular usage.

Patch / fix

  • julia HDF5_jll 2.1.0+0
  • hdfgroup hdf5 2.0.0
  • hdf5 Debian 14 2.1.0+repack-1

debian advisories DEBIAN-CVE-2026-26197

  • hdf5 hummingbird 1 2.2.0-0.1.1.hum1
  • java-hdf5 hummingbird 1 2.2.0-0.1.1.hum1
  • hdf5-mpich hummingbird 1 2.2.0-0.1.1.hum1
  • hdf5-openmpi hummingbird 1 2.2.0-0.1.1.hum1

red hat advisories RHSA-2026:61630

  • hdf5 Azure Linux 3.0 1.14.6-4

azure linux advisories AZL-92847

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-26197 updated cvss 5.3

hdf5: HDF5: Out-of-bounds read due to corrupted file can lead to denial of service

  • Red Hat AI Inference Server rhaii/vllm-cpu-rhel9, rhaii/vllm-tpu-rhel9, rhaii/vllm-cuda-rhel9, rhaii/vllm-rocm-rhel9, rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9, +9 more Red Hat Enterprise Linux AI (RHEL AI) 3 hdf5, rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-gcp-cuda-rhel9, +2 more Red Hat OpenShift AI (RHOAI) rhoai/odh-automl-rhel9, rhoai/odh-autorag-rhel9, rhoai/odh-mlserver-rhel9, rhai/base-image-cpu-rhel9, rhai/base-image-tpu-rhel9, rhai/base-image-gaudi-rhel9, +24 more
    affected: no fix available “Fix deferred”
  • Red Hat Hardened Images hdf5 2.2.0-0.1.1.hum1
    fixed: vendor fix RHSA-2026:61630

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/HDFGroup/hdf5/security/advisories/GHSA-gh44-7wpq-622f referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.9 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
CNA 4.0 5.9 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 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
julia HDF5_jll
<2.1.0+0
2.1.0+0

Affected products

  • HDFGroup hdf5

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.