Hitachi Dynamic Link Manager for Linux: Incorrect Calculation of Buffer Size
CVE-2026-91758 is a high-severity incorrect calculation of buffer size vulnerability in Hitachi Dynamic Link Manager for Linux from Hitachi, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 9.0.5-00 as the first without the flaw, so updating Hitachi Dynamic Link Manager for Linux to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.15% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Hitachi Dynamic Link Manager for Linux to 9.0.5-00 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Hitachi | Hitachi Dynamic Link Manager for Linux | 7.5.0-00 up to, but not including, 9.0.5-00 | 9.0.5-00 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (hitachi.co.jp).
Official description
Out-of-bounds Read and Write Vulnerability in Hitachi Dynamic Link Manager for Linux. This issue affects Hitachi Dynamic Link Manager for Linux: from 7.5.0-00 before 9.0.5-00.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Calculation of Buffer Size
The product does not correctly calculate the size to be used when allocating a buffer.
How developers prevent this class of flaw
- When allocating a buffer for the purpose of transforming, converting, or encoding an input, allocate enough memory to handle the largest possible encoding. For example, in a routine that converts & characters to & for HTML entity encoding, the output buffer needs to be at least 5 times as large as the input buffer.
- Understand the programming language's underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, not-a-number calculations, and how the language handles numbers that are too large or too small for its underlying representation. Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.
- Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
More Incorrect Calculation of Buffer Size vulnerabilities (CWE-131)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
References
Other vulnerabilities in Hitachi Dynamic Link Manager for Linux
- 8.1 High severity
- 8.2 High severity
- 7.9 High severity
- 8.2 High severity
- 7.0 High severity
- 7.8 High severity
Recent Incorrect Calculation of Buffer Size vulnerabilities
- 7.5 High severity
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
- 7.5 High severity
- 7.8 High severity
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