{"id":"UBUNTU-CVE-2026-73639","details":"Imager::File::PNG versions from 1.003 before 1.004 for Perl write past the end of the row buffer reading a PNG with a tRNS transparency chunk in read_direct8. With a tRNS chunk, read_direct8() adds an alpha channel to the image it creates but still sizes the row buffer from the original channel count. libpng expands the transparency into that extra channel, so png_read_row() fills one channel more than the buffer holds, at one byte per sample, and writes width bytes past the end of the allocation. Palette images go to read_paletted() and 16-bit images to read_direct16(), which sizes its buffer from png_get_rowbytes() and allocates enough for the expanded row. The same reader ships bundled in the Imager distribution. Reading an attacker-supplied PNG through Imager-\u003eread() corrupts the heap, which can crash the process.","modified":"2026-09-24T02:00:52.035895822Z","published":"2026-09-17T22:17:00Z","upstream":["CVE-2026-73639"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-73639"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-73639"},{"type":"REPORT","url":"https://github.com/tonycoz/imager/security/advisories/GHSA-jhx5-34j8-9g88"},{"type":"REPORT","url":"https://github.com/tonycoz/imager/pull/567"}],"affected":[{"package":{"name":"libimager-perl","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/libimager-perl?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.003+dfsg-1","1.004+dfsg-1","1.004+dfsg-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libimager-perl","binary_version":"1.004+dfsg-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73639.json"}},{"package":{"name":"libimager-perl","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/libimager-perl?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.005+dfsg-2build1","1.006+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libimager-perl","binary_version":"1.006+dfsg-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73639.json"}},{"package":{"name":"libimager-perl","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/libimager-perl?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.011+dfsg-1","1.011+dfsg-1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.011+dfsg-1build1","binary_name":"libimager-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73639.json"}},{"package":{"name":"libimager-perl","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libimager-perl?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.012+dfsg-1build1","1.012+dfsg-2","1.012+dfsg-2build1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.012+dfsg-2build1","binary_name":"libimager-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73639.json"}},{"package":{"name":"libimager-perl","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libimager-perl?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.019+dfsg-2","1.020+dfsg-1","1.022+dfsg-1","1.023+dfsg-1","1.023+dfsg-1build1","1.023+dfsg-1build2"],"ecosystem_specific":{"binaries":[{"binary_name":"libimager-perl","binary_version":"1.023+dfsg-1build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73639.json"}},{"package":{"name":"libimager-perl","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libimager-perl?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.027+dfsg-1","1.029+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.029+dfsg-1","binary_name":"libimager-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73639.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}