{"id":"CVE-2026-84383","title":"libheif is a HEIF and AVIF file format decoder and encoder","summary":"libheif is a HEIF and AVIF file format decoder and encoder. From 1.22.0 until 1.23.2, a crafted HEIF, HEIC, or AVIF item graph using nested iden and auxl references can make HeifPixelImage::transfer_channel_from_image_as() append duplica…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-787"],"vendor":"strukturag","product":"libheif","affected":["libheif >= 1.22.0, < 1.23.2"],"published":"2026-09-18","updated":"2026-09-18","sourceUpdated":"2026-09-18T16:17:11.853","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-84383","references":[{"url":"https://github.com/strukturag/libheif/commit/f4fb8bde4704ebb46e46ff9fb94407c9774153b2","label":"security-advisories@github.com"},{"url":"https://github.com/strukturag/libheif/releases/tag/v1.23.2","label":"security-advisories@github.com"},{"url":"https://github.com/strukturag/libheif/security/advisories/GHSA-g89c-p67h-r497","label":"security-advisories@github.com"},{"url":"https://github.com/strukturag/libheif/security/advisories/GHSA-g89c-p67h-r497","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-84383.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-84383"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2538121"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-84383"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84383"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat","score-dispute"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"total","timestamp":"2026-09-18T16:07:46.621200Z"},"ingestedAt":"2026-09-18T16:45:41.392Z","epss":0.00717,"epssPercentile":0.53623,"scores":{"nvd":9.8,"vendor":7.8},"exploits":{"github":1,"githubRepos":["https://github.com/dinosn/libheif-cve-2026-84383-lab"],"checkedAt":"2026-10-27T19:17:22.415Z"},"slug":"CVE-2026-84383","body":"## Overview\n\nlibheif is a HEIF and AVIF file format decoder and encoder. From 1.22.0 until 1.23.2, a crafted HEIF, HEIC, or AVIF item graph using nested iden and auxl references can make HeifPixelImage::transfer_channel_from_image_as() append duplicate Alpha planes with different bit depths to m_storage. HeifPixelImage::scale_nearest_neighbor() in libheif/image/pixelimage.cc allocates the destination Alpha plane using the first plane's 8-bit depth, then iterates a later 10-bit or 12-bit Alpha component and writes uint16_t samples into the same 8-bit allocation. The output geometry controls the overflow extent and the encoded sample values control the data written, allowing a remote file processed by heif_decode_image() to cause a heap out-of-bounds write. This issue is fixed in version 1.23.2.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Critical · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-84383.json)","depth":"abyssal","depthScore":66,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}