CVE-2026-31963
Description
A flaw was found in HTSlib, a library for reading and writing bioinformatics file formats. When processing CRAM (Compressed Reference-oriented Alignment Map) files, an out-by-one error in feature decoding can cause a heap buffer overflow. This vulnerability allows an attacker to craft a malicious CRAM file which, when opened by a user, could lead to a program crash, data corruption, or potentially arbitrary code execution.
Statement
This is an IMPORTANT flaw due to a heap buffer overflow in the HTSlib CRAM reader when processing specially crafted CRAM files. This flaw requires user interaction, as it is triggered when an application linked against HTSlib opens a malicious CRAM file, potentially leading to arbitrary code execution or data corruption.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Instability
This weakness will generally lead to undefined behavior and therefore crashes. In the case of overflows involving loop index variables, the likelihood of infinite loops is also high.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the wrap around results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.
Frequently Asked Questions
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