CVE-2026-31963

HIGH EPSS 26.7%
Published Mar 18, 20263mo ago · Modified Mar 19, 20263mo ago
8.8 CVSS 4.0
High
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. As one method of removing redundant data, CRAM uses reference-based compression so that instead of storing the full sequence for each alignment record it stores a location in an external reference sequence along with a list of differences to the reference at that location as a sequence of "features". When decoding these features, an out-by-one error in a test for CRAM features that appear beyond the extent of the CRAM record sequence could result in an invalid write of one attacker-controlled byte beyond the end of a heap buffer. Exploiting this bug causes a heap buffer overflow. If a user opens a file crafted to exploit this issue, it could lead to the program crashing, or overwriting of data and heap structures in ways not expected by the program. It may be possible to use this to obtain arbitrary code execution. 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
8.8
Exploitability
Impact
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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
26.7% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 3

CWE-122
CWE-129
CWE-787 Out-of-bounds Write 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/8bcc9907be0f945ddc31796d64f078fa05456acd
    Patch
  • github.com https://github.com/samtools/htslib/security/advisories/GHSA-qgqh-h2q9-7w3c
    PatchVendor Advisory

Remediation

  • github.com https://github.com/samtools/htslib/commit/8bcc9907be0f945ddc31796d64f078fa05456acd
    Patch
  • github.com https://github.com/samtools/htslib/security/advisories/GHSA-qgqh-h2q9-7w3c
    PatchVendor Advisory