{"id":"UBUNTU-CVE-2026-19027","details":"The H5Z__nbit_decompress_one_byte, H5Z__nbit_decompress_one_nooptype, and H5Z__nbit_decompress_one_atomic functions in H5Znbit.c in HDF5 through 2.3.0 advance a read index into the compressed chunk buffer without bounding it against the buffer's actual size. This allows attackers to cause an out-of-bounds heap read, and in constrained cases disclosure of adjacent heap memory into decompressed dataset values, via a crafted HDF5 file whose N-Bit filter parameters describe more decompressed data than the stored compressed chunk actually contains, triggered via H5Dread, e.g. by the h5ls or h5repack tools.","modified":"2026-08-13T00:02:19Z","published":"2026-08-06T00:16:00Z","upstream":["CVE-2026-19027"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-19027"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-19027"},{"type":"REPORT","url":"https://github.com/HDFGroup/hdf5/pull/6497"},{"type":"REPORT","url":"https://github.com/HDFGroup/hdf5/issues/6489"},{"type":"REPORT","url":"https://github.com/HDFGroup/hdf5/issues/6492"}],"affected":[{"package":{"name":"hdf5","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/hdf5?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.8.11-3ubuntu1","1.8.11-5ubuntu1","1.8.11-5ubuntu2","1.8.11-5ubuntu6","1.8.11-5ubuntu7","1.8.11-5ubuntu7.1","1.8.11-5ubuntu7.1+esm1","1.8.11-5ubuntu7.1+esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.8.11-5ubuntu7.1+esm2","binary_name":"hdf5-helpers"},{"binary_name":"hdf5-tools","binary_version":"1.8.11-5ubuntu7.1+esm2"},{"binary_name":"libhdf5-7","binary_version":"1.8.11-5ubuntu7.1+esm2"},{"binary_name":"libhdf5-mpich2-7","binary_version":"1.8.11-5ubuntu7.1+esm2"},{"binary_name":"libhdf5-openmpi-7","binary_version":"1.8.11-5ubuntu7.1+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19027.json"}},{"package":{"name":"hdf5","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/hdf5?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.8.15-patch1+docs-4","1.8.15-patch1+docs-5","1.8.16+docs-1","1.8.16+docs-2","1.8.16+docs-3","1.8.16+docs-3ubuntu1","1.8.16+docs-4","1.8.16+docs-4ubuntu1","1.8.16+docs-4ubuntu1.1","1.8.16+docs-4ubuntu1.1+esm1","1.8.16+docs-4ubuntu1.1+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"hdf5-helpers","binary_version":"1.8.16+docs-4ubuntu1.1+esm2"},{"binary_name":"hdf5-tools","binary_version":"1.8.16+docs-4ubuntu1.1+esm2"},{"binary_name":"libhdf5-10","binary_version":"1.8.16+docs-4ubuntu1.1+esm2"},{"binary_name":"libhdf5-cpp-11","binary_version":"1.8.16+docs-4ubuntu1.1+esm2"},{"binary_name":"libhdf5-mpich-10","binary_version":"1.8.16+docs-4ubuntu1.1+esm2"},{"binary_name":"libhdf5-openmpi-10","binary_version":"1.8.16+docs-4ubuntu1.1+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19027.json"}},{"package":{"name":"hdf5","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/hdf5?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.0-patch1+docs-4","1.10.0-patch1+docs-4ubuntu0.1~esm1","1.10.0-patch1+docs-4ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.10.0-patch1+docs-4ubuntu0.1~esm2","binary_name":"hdf5-helpers"},{"binary_name":"hdf5-tools","binary_version":"1.10.0-patch1+docs-4ubuntu0.1~esm2"},{"binary_name":"libhdf5-100","binary_version":"1.10.0-patch1+docs-4ubuntu0.1~esm2"},{"binary_version":"1.10.0-patch1+docs-4ubuntu0.1~esm2","binary_name":"libhdf5-cpp-100"},{"binary_name":"libhdf5-java","binary_version":"1.10.0-patch1+docs-4ubuntu0.1~esm2"},{"binary_name":"libhdf5-jni","binary_version":"1.10.0-patch1+docs-4ubuntu0.1~esm2"},{"binary_name":"libhdf5-mpich-100","binary_version":"1.10.0-patch1+docs-4ubuntu0.1~esm2"},{"binary_name":"libhdf5-openmpi-100","binary_version":"1.10.0-patch1+docs-4ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19027.json"}},{"package":{"name":"hdf5","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/hdf5?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.4+repack-10","1.10.4+repack-11","1.10.4+repack-11ubuntu1","1.10.4+repack-11ubuntu1+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"hdf5-helpers","binary_version":"1.10.4+repack-11ubuntu1+esm1"},{"binary_name":"hdf5-tools","binary_version":"1.10.4+repack-11ubuntu1+esm1"},{"binary_name":"libhdf5-103","binary_version":"1.10.4+repack-11ubuntu1+esm1"},{"binary_name":"libhdf5-cpp-103","binary_version":"1.10.4+repack-11ubuntu1+esm1"},{"binary_version":"1.10.4+repack-11ubuntu1+esm1","binary_name":"libhdf5-java"},{"binary_name":"libhdf5-jni","binary_version":"1.10.4+repack-11ubuntu1+esm1"},{"binary_name":"libhdf5-mpich-103","binary_version":"1.10.4+repack-11ubuntu1+esm1"},{"binary_name":"libhdf5-openmpi-103","binary_version":"1.10.4+repack-11ubuntu1+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19027.json"}},{"package":{"name":"hdf5","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/hdf5?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.6+repack-5","1.10.7+repack-4ubuntu1","1.10.7+repack-4ubuntu2"],"ecosystem_specific":{"binaries":[{"binary_name":"hdf5-helpers","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"hdf5-tools"},{"binary_name":"libhdf5-103","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-103-1"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-cpp-103"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-cpp-103-1"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-fortran-102"},{"binary_name":"libhdf5-hl-100","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-hl-cpp-100"},{"binary_name":"libhdf5-hl-fortran-100","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_name":"libhdf5-java","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-jni"},{"binary_name":"libhdf5-mpich-103","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-mpich-103-1"},{"binary_name":"libhdf5-mpich-cpp-103-1","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_name":"libhdf5-mpich-fortran-102","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_name":"libhdf5-mpich-hl-100","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_name":"libhdf5-mpich-hl-cpp-100","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_name":"libhdf5-mpich-hl-fortran-100","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-openmpi-103"},{"binary_name":"libhdf5-openmpi-103-1","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_version":"1.10.7+repack-4ubuntu2","binary_name":"libhdf5-openmpi-cpp-103-1"},{"binary_name":"libhdf5-openmpi-fortran-102","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_name":"libhdf5-openmpi-hl-100","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_name":"libhdf5-openmpi-hl-cpp-100","binary_version":"1.10.7+repack-4ubuntu2"},{"binary_name":"libhdf5-openmpi-hl-fortran-100","binary_version":"1.10.7+repack-4ubuntu2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19027.json"}},{"package":{"name":"hdf5","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/hdf5?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.8+repack1-1ubuntu1","1.10.10+repack-3ubuntu1","1.10.10+repack-3.1ubuntu3","1.10.10+repack-3.1ubuntu4"],"ecosystem_specific":{"binaries":[{"binary_name":"hdf5-helpers","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"hdf5-tools"},{"binary_name":"libhdf5-103-1t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_name":"libhdf5-cpp-103-1t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_name":"libhdf5-fortran-102t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"libhdf5-hl-100t64"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"libhdf5-hl-cpp-100t64"},{"binary_name":"libhdf5-hl-fortran-100t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"libhdf5-java"},{"binary_name":"libhdf5-jni","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_name":"libhdf5-mpich-103-1t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_name":"libhdf5-mpich-cpp-103-1t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_name":"libhdf5-mpich-fortran-102t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_name":"libhdf5-mpich-hl-100t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"libhdf5-mpich-hl-cpp-100t64"},{"binary_name":"libhdf5-mpich-hl-fortran-100t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_name":"libhdf5-openmpi-103-1t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"libhdf5-openmpi-cpp-103-1t64"},{"binary_name":"libhdf5-openmpi-fortran-102t64","binary_version":"1.10.10+repack-3.1ubuntu4"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"libhdf5-openmpi-hl-100t64"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"libhdf5-openmpi-hl-cpp-100t64"},{"binary_version":"1.10.10+repack-3.1ubuntu4","binary_name":"libhdf5-openmpi-hl-fortran-100t64"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19027.json"}},{"package":{"name":"hdf5","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/hdf5?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.14.5+repack-3build1","1.14.5+repack-4","1.14.6+repack-2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.14.6+repack-2","binary_name":"hdf5-helpers"},{"binary_name":"hdf5-tools","binary_version":"1.14.6+repack-2"},{"binary_version":"1.14.6+repack-2","binary_name":"libhdf5-310"},{"binary_name":"libhdf5-cpp-310","binary_version":"1.14.6+repack-2"},{"binary_name":"libhdf5-fortran-310","binary_version":"1.14.6+repack-2"},{"binary_name":"libhdf5-hl-310","binary_version":"1.14.6+repack-2"},{"binary_name":"libhdf5-hl-cpp-310","binary_version":"1.14.6+repack-2"},{"binary_version":"1.14.6+repack-2","binary_name":"libhdf5-hl-fortran-310"},{"binary_name":"libhdf5-java","binary_version":"1.14.6+repack-2"},{"binary_name":"libhdf5-jni","binary_version":"1.14.6+repack-2"},{"binary_name":"libhdf5-mpich-310","binary_version":"1.14.6+repack-2"},{"binary_version":"1.14.6+repack-2","binary_name":"libhdf5-mpich-cpp-310"},{"binary_version":"1.14.6+repack-2","binary_name":"libhdf5-mpich-fortran-310"},{"binary_version":"1.14.6+repack-2","binary_name":"libhdf5-mpich-hl-310"},{"binary_name":"libhdf5-mpich-hl-cpp-310","binary_version":"1.14.6+repack-2"},{"binary_name":"libhdf5-mpich-hl-fortran-310","binary_version":"1.14.6+repack-2"},{"binary_name":"libhdf5-openmpi-310","binary_version":"1.14.6+repack-2"},{"binary_version":"1.14.6+repack-2","binary_name":"libhdf5-openmpi-cpp-310"},{"binary_version":"1.14.6+repack-2","binary_name":"libhdf5-openmpi-fortran-310"},{"binary_name":"libhdf5-openmpi-hl-310","binary_version":"1.14.6+repack-2"},{"binary_version":"1.14.6+repack-2","binary_name":"libhdf5-openmpi-hl-cpp-310"},{"binary_name":"libhdf5-openmpi-hl-fortran-310","binary_version":"1.14.6+repack-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19027.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}