HDF5, Null Pointer Dereference, CVE-2025-2926 (Medium)

How CVE-2025-2926 Works

The vulnerability exists in the `H5O__cache_chk_serialize` function within `src/H5Ocache.c` in HDF5 versions up to 1.14.6. A null pointer dereference occurs when processing malformed HDF5 files, triggered during serialization checks in the object cache. Attackers can exploit this by crafting a malicious file, causing a denial-of-service (crash) when parsed. The flaw requires local access, limiting remote exploitation potential. The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:L/UI:N) reflects its medium severity due to low attack complexity but constrained impact (VA:L).

DailyCVE Form

Platform: HDF5
Version: ≤1.14.6
Vulnerability: Null dereference
Severity: Medium
Date: 04/17/2025

What Undercode Say:

Exploitation

1. Craft a malformed HDF5 file triggering `H5O__cache_chk_serialize`:

import h5py
with h5py.File('exploit.h5', 'w') as f:
f.create_dataset('payload', data=b'\x00'1024) PoC structure

2. Local execution via vulnerable apps:

./vulnerable_app exploit.h5

Detection

Scan for HDF5 versions:

ldconfig -p | grep libhdf5

Mitigation

1. Patch to HDF5 1.14.7+:

wget https://www.hdfgroup.org/downloads/hdf5-1.14.7.tar.gz
tar -xzvf hdf5-1.14.7.tar.gz
cd hdf5-1.14.7 && ./configure && make && sudo make install

2. Runtime protection:

echo 0 | sudo tee /proc/sys/kernel/ptr_restrict Temporary hardening

3. Code audit for `H5Ocache.c`:

// Patch snippet: Add NULL checks
if (obj == NULL) {
H5O__cache_chk_cleanup();
return FAIL;
}

Analytics

Attack Surface: Local file processing
Exploitability: Low (requires user interaction)

Affected Distributions:

grep -r "libhdf5" /etc/apt/sources.list.d/