CVE-2026-31971CWE-121CWE-122CWE-1284CWE-787

HTSlib CRAM decoder vulnerable to buffer overflow

High · published March 18, 2026

CVSS v4.0
7.1
EPSS
1%
Percentile
44.6
In the wild
Unconfirmed
What it is

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. When reading data encoded using the `BYTE_ARRAY_LEN` method, the `cram_byte_array_len_decode()` failed to validate that the amount of data being unpacked matched the size of the output buffer where it was to be stored. Depending on the data series being read, this could result either in a heap or a stack overflow with attacker-controlled bytes. Depending on the data stream this could result either in a heap buffer overflow or a stack overflow. If a user opens a file crafted to exploit this issue it could lead to the program crashing, overwriting of data structures on the heap or stack in ways not expected by the program, or changing the control flow of 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.

The record
Technical detail
CVSS v4.0
7.1 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
EPSS
0.00540 · 44.6th percentile
Weaknesses
CWE-121 · Stack-based Buffer Overflow; CWE-122 · Heap-based Buffer Overflow; CWE-1284 · Improper Validation of Specified Quantity in Input; CWE-787 · Out-of-bounds Write
Published
2026-03-18T19:55Z
EPSS history
Timeline
  • 18 MAR 19:55Z
    HTSlib CRAM decoder vulnerable to buffer overflow
    cvelistv5