CVE-2026-120754
Description
A flaw was found in HDF5. This vulnerability allows an attacker to cause information disclosure by convincing a user or application to process a specially crafted HDF5 file. During decompression, bounds checks incorrectly evaluate the buffer's total allocated size rather than the actual amount of data read, resulting in an uninitialized memory read. Consequently, unrelated heap memory contents can be returned, potentially exposing sensitive process data.
Statement
An uninitialized memory read vulnerability was found in HDF5's H5Z__filter_scaleoffset() function in src/H5Zscaleoffset.c. When decompressing a dataset from a crafted HDF5 file containing a truncated chunk, the library validates reads against the allocated chunk buffer size rather than the actual bytes read, returning uninitialized heap memory to the caller. An attacker who convinces a user or application to read a dataset from a specially crafted HDF5 file can trigger this flaw to leak sensitive process memory.
Mitigation
Restrict file access permissions to ensure HDF5 files are ingested exclusively from verified, trusted sources. Isolate applications decompressing untrusted HDF5 files inside containerized or memory-constrained sandbox environments to minimize the sensitivity of process memory exposed.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.3 | 3.3 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory; Read Application Data
When reusing a resource such as memory or a program variable, the original contents may not have been cleared before it is sent to an untrusted party.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Instability
The uninitialized resource may contain values that cause program flow to change in ways that the programmer did not intend, possibly leading to a crash.
Other
Technical Impact: Unexpected State; Varies by Context
The consequences vary depending on the type of resource and how it is used within the product.
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