CVE-2026-86095: Out-of-bounds Write in Unidata netcdf-c

CVE-2026-86095 is an out-of-bounds write vulnerability in Unidata netcdf-c through version 4.10.1. The vulnerability exists in the NC4_HDF5_inq_attname() function, which copies HDF5 attribute names into a fixed-size 256-byte buffer without checking if the attribute name length exceeds this buffer size. An attacker can exploit this by providing an HDF5 file with attribute names longer than 256 bytes, causing a buffer overflow that results in memory corruption and potential application crashes when enumerating attribute names.

Successful exploitation can cause memory corruption and application crashes in software using the vulnerable netcdf-c library when processing maliciously crafted HDF5 files with oversized attribute names. This may lead to denial of service or potentially other undefined behavior due to memory corruption. There is no indication of privilege escalation or remote code execution in the provided data.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid processing untrusted HDF5 files with the vulnerable netcdf-c versions to mitigate risk.