CVE-2026-31964

MEDIUM EPSS 24.0%
Published Mar 18, 20263mo ago · Modified Mar 19, 20263mo ago
6.9 CVSS 4.0
Medium
Find Similar
Published Mar 18, 2026 3mo ago
Last Modified Mar 19, 2026 3mo ago

Description

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data using a variety of encodings and compression methods. While most alignment records store DNA sequence and quality values, the format also allows them to omit this data in certain cases to save space. Due to some quirks of the CRAM format, it is necessary to handle these records carefully as they will actually store data that needs to be consumed and then discarded. Unfortunately the `CONST`, `XPACK` and `XRLE` encodings did not properly implement the interface needed to do this. Trying to decode records with omitted sequence or quality data using these encodings would result in an attempt to write to a NULL pointer. Exploiting this bug causes a NULL pointer dereference. Typically this will cause the program to crash. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

CVSS Details

Base Score
6.9
Exploitability
Impact
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
24.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-476 NULL Pointer Dereference Memory Safety

Affected Products 3

VendorProductVersionRange
htslibhtslib* <1.21.1
htslibhtslib*≥1.22  –  <1.22.2
htslibhtslib1.23any

References 2

  • github.com https://github.com/samtools/htslib/commit/e64e68da567d2309509d059ace016d5d7fc7514f
    Patch
  • github.com https://github.com/samtools/htslib/security/advisories/GHSA-5w97-85gf-86rm
    PatchVendor Advisory

Remediation

  • github.com https://github.com/samtools/htslib/commit/e64e68da567d2309509d059ace016d5d7fc7514f
    Patch
  • github.com https://github.com/samtools/htslib/security/advisories/GHSA-5w97-85gf-86rm
    PatchVendor Advisory