CVE-2026-120756
Description
A flaw was found in hdf5. When parsing object header messages, insufficient boundary checks can allow an attacker to trigger a heap buffer over-read by convincing a user or application to open a specially crafted file. Successful exploitation could cause the application to crash, resulting in a Denial of Service (DoS), or potentially lead to limited disclosure of process memory.
Statement
A heap-based buffer over-read vulnerability was found in HDF5's H5O__chunk_deserialize() function in src/H5Ocache.c. When decoding object header messages from a crafted file via H5Fopen(), the library validates the declared message size against the chunk boundary before decoding trailing header fields, causing message bodies to offset up to four bytes beyond the checked boundary. An attacker who tricks a user or application into opening a specially crafted HDF5 file can cause an application crash, resulting in a denial of service, or potentially leak limited process memory.
Mitigation
Restrict file access permissions to ensure HDF5 files are ingested exclusively from trusted sources. Run processing applications within sandboxed or containerized environments with strict resource constraints to isolate process termination and mitigate potential memory exposure.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.4 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | Required | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | Low | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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