CVE-2026-31965
Description
A flaw was found in HTSlib, a library for reading and writing bioinformatics file formats. This vulnerability, an out-of-bounds read, occurs in the cram_decode_slice() function when processing CRAM (Compressed Reference-oriented Alignment Map) records due to delayed validation of the reference ID field. A remote attacker could exploit this by providing a specially crafted CRAM file, potentially leading to the disclosure of two memory values or causing the program to crash, resulting in a Denial of Service (DoS).
Statement
MODERATE impact: The HTSlib CRAM reader is vulnerable to out-of-bounds reads due to improper input validation. This flaw can lead to information leakage or application crashes when processing specially crafted CRAM files. This affects components utilizing HTSlib for CRAM file processing, such as htslib and python-pysam in Community Projects (EPEL and Fedora).
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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