CVE-2025-2914

Executive Summary

CVE-2025-2914 is a heap-based buffer overflow vulnerability in the HDF5 library, affecting versions up to and including 1.14.6. The flaw resides in the H5FS__sinfo_Srialize_Sct_cb function within src/H5FScache.c. An attacker with local access can trigger a heap overflow by manipulating the sect argument, potentially leading to memory corruption or denial of service. The vulnerability has a low CVSS score of 3.3 due to the requirement for local access and limited impact on confidentiality and integrity. A patch is available, and the exploit has been publicly disclosed.

Supply Chain & Package Security

This vulnerability affects the HDF5 library, which is widely used in scientific computing, data analysis, and various open-source projects. Organizations using HDF5 in their software supply chain should assess their exposure and prioritize patching. The library is distributed via source code and package managers (e.g., conda, vcpkg, Homebrew). Ensure that all dependencies are updated to a patched version.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
• Base Score: 3.3 (Low)
• Attack Vector: Local (AV:L) – Requires local system access.
• Attack Complexity: Low (AC:L) – No special conditions needed.
• Privileges Required: Low (PR:L) – Attacker needs basic user privileges.
• User Interaction: None (UI:N) – No user action required.
• Scope: Unchanged (S:U) – Impact confined to the vulnerable component.
• Confidentiality Impact: None (C:N)
• Integrity Impact: None (I:N)
• Availability Impact: Low (A:L) – Potential for denial of service or memory corruption.

Threat Level: Low. The requirement for local access significantly reduces the attack surface. However, in multi-user environments or systems where untrusted users can execute code, this vulnerability could be exploited to cause instability.

Deep Dive & Mechanics

The vulnerability is a heap-based buffer overflow in the HDF5 library's free-space manager. The function H5FS__sinfo_Srialize_Sct_cb is responsible for serializing section information. When processing the sect argument, it fails to properly validate the size of the data being written to a heap buffer. By providing a specially crafted sect value, an attacker can cause the function to write beyond the allocated buffer, corrupting adjacent heap memory.

Root Cause: Insufficient bounds checking on the sect parameter before memory copy operations. The code does not verify that the size of the section data fits within the allocated buffer.

Impact: Heap corruption can lead to:

• Denial of service (crash)
• Potential arbitrary code execution (though less likely due to heap protections)

Attack Vector: Local access. An attacker must be able to execute code on the target system and trigger the vulnerable function, typically by opening a malicious HDF5 file.

Vulnerable vs. Patched Code

Vulnerable Code (HDF5 <= 1.14.6):

// src/H5FScache.c (simplified)
herr_t H5FS__sinfo_Srialize_Sct_cb(void *item, void *key, void *udata) {
    H5FS_section_info_t *sect = (H5FS_section_info_t *)item;
    // ... 
    // No size check before memcpy
    memcpy(buf + offset, sect->data, sect->size);
    // ...
}

Patched Code (HDF5 > 1.14.6):

// src/H5FScache.c (simplified)
herr_t H5FS__sinfo_Srialize_Sct_cb(void *item, void *key, void *udata) {
    H5FS_section_info_t *sect = (H5FS_section_info_t *)item;
    // ...
    // Added bounds check
    if ((offset + sect->size) > buf_size) {
        // Handle error
        return FAIL;
    }
    memcpy(buf + offset, sect->data, sect->size);
    // ...
}

The patch adds a validation check to ensure that the section data does not exceed the buffer boundaries before performing the memory copy.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Local access to a system running HDF5 <= 1.14.6
• Ability to create or modify HDF5 files

Exploit Concept:

1. Craft a malicious HDF5 file with a free-space section containing an oversized sect value.
2. When the target application opens the file and processes the free-space manager, the vulnerable function is called.
3. The oversized sect causes a heap buffer overflow, potentially corrupting adjacent data.

Proof-of-Concept (PoC):

# poc.py - Simplified PoC for CVE-2025-2914
import h5py
import numpy as np

# Create a malicious HDF5 file
with h5py.File('malicious.h5', 'w') as f:
    # Create a dataset to trigger free-space manager
    dset = f.create_dataset('data', (100,), dtype='i4')
    # Manipulate internal structures (requires low-level access)
    # This is a conceptual example; actual exploitation requires
    # crafting the binary file directly.
    pass

Note: The actual exploit requires low-level manipulation of HDF5 file structures. The PoC above is illustrative.

Blue Team (Detection & Defense)

Detection:

• Monitor for crashes or abnormal behavior in applications using HDF5.
• Use memory analysis tools (e.g., Valgrind, AddressSanitizer) to detect heap overflows.
• Implement file integrity monitoring for HDF5 files.

Defense:

• Apply the patch immediately (upgrade to HDF5 > 1.14.6).
• Restrict local access to trusted users only.
• Use sandboxing or containerization to limit the impact of local exploits.
• Enable heap protection mechanisms (e.g., ASLR, DEP).

Indicators of Compromise (IOCs)

• File Hashes (malicious HDF5 files):
  • SHA256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (example)
• Behavioral IOCs:
  • Unexpected crashes in HDF5-based applications
  • Heap corruption errors in system logs
  • Abnormal memory allocation patterns
• Network IOCs: None (local vulnerability)

Detection Engineering

YARA Rule

rule CVE_2025_2914_HDF5_HeapOverflow {
    meta:
        description = "Detects HDF5 files potentially exploiting CVE-2025-2914"
        author = "Valters IT"
        date = "2025-04-17"
        reference = "CVE-2025-2914"
    strings:
        $hdf5_magic = { 89 48 44 46 0D 0A 1A 0A }  // HDF5 magic bytes
        $sect_pattern = { ?? ?? ?? ?? 00 00 00 00 } // Oversized sect field
    condition:
        $hdf5_magic at 0 and #sect_pattern > 0
}

Sigma Rule

title: CVE-2025-2914 HDF5 Heap Overflow Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects potential exploitation of CVE-2025-2914 via heap corruption
author: Valters IT
date: 2025-04-17
logsource:
    category: application
    product: hdf5
detection:
    selection:
        EventID: 1000  # Application crash
        Application: "*hdf5*"
        ExceptionCode: 0xc0000005  # Access violation
    condition: selection
falsepositives:
    - Legitimate crashes due to other bugs
level: medium

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-2914 HDF5 Heap Overflow Attempt"; flow:to_server; content:"|89 48 44 46 0D 0A 1A 0A|"; depth:8; content:"|00 00 00 00|"; within:4; reference:cve,2025-2914; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Patch: Upgrade HDF5 to version > 1.14.6. The patch is available from the official HDF5 repository.
2. Workaround: If patching is not immediately possible, restrict local access to trusted users and avoid opening untrusted HDF5 files.

Long-Term Measures:

• Implement code review and static analysis for memory safety.
• Use memory-safe languages or libraries where possible.
• Enable compiler hardening flags (e.g., -fstack-protector-strong, -D_FORTIFY_SOURCE=2).
• Regularly update dependencies and monitor for CVEs.

Verification:

• After patching, verify the fix by checking the version: h5dump --version should show > 1.14.6.
• Run regression tests to ensure no side effects.

Valters IT
Securing Digital Frontiers