{"id":"CVE-2026-62291","state":"PUBLISHED","title":"libheif: Heap out of bounds write in libheif uncompressed encoder when writing images with mismatched auxiliary alpha dimensions","description":"libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted image sequence with a 2x2 primary plane and a 256x256 auxiliary alpha plane can cause attacker-controlled heap corruption during a normal decode and re-encode workflow. Track_Visual::decode_next_image_sample() calls transfer_channel_from_image_as() without checking that the auxiliary alpha dimensions match the main frame. The resulting inconsistent image reaches heif_track_decode_next_image() and then heif_context_encode_image(). In unc_encoder::encode(), unc_encoder_component_interleave::encode_tile() sizes its buffer with compute_tile_data_size_bytes() using the primary dimensions but copies each component using its actual plane dimensions. The oversized alpha plane is therefore copied beyond the allocation, causing an out-of-bounds write; the inverse size mismatch can also produce an out-of-bounds read. This issue is fixed in version 1.23.1.","publishedAt":"2026-08-18T21:21:32.182Z","updatedAt":"2026-08-21T19:11:12.114Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["strukturag libheif"],"affected":[{"vendor":"strukturag","product":"libheif","versions":[{"version":"< 1.23.1","status":"affected"}]}],"references":["https://github.com/strukturag/libheif/security/advisories/GHSA-xpw3-9rhw-482x","https://github.com/strukturag/libheif/commit/ac5521ad50399885de96bb6a0733a5d2442740f9","https://github.com/strukturag/libheif/releases/tag/v1.23.1"],"weaknesses":["CWE-125","CWE-787"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/62xxx/CVE-2026-62291.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-62291","state":"PUBLISHED","datePublished":"2026-08-18T21:21:32.182Z","dateUpdated":"2026-08-21T19:11:12.114Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-13T18:37:08.488Z"},"containers":{"cna":{"title":"libheif: Heap out of bounds write in libheif uncompressed encoder when writing images with mismatched auxiliary alpha dimensions","descriptions":[{"lang":"en","value":"libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted image sequence with a 2x2 primary plane and a 256x256 auxiliary alpha plane can cause attacker-controlled heap corruption during a normal decode and re-encode workflow. Track_Visual::decode_next_image_sample() calls transfer_channel_from_image_as() without checking that the auxiliary alpha dimensions match the main frame. The resulting inconsistent image reaches heif_track_decode_next_image() and then heif_context_encode_image(). In unc_encoder::encode(), unc_encoder_component_interleave::encode_tile() sizes its buffer with compute_tile_data_size_bytes() using the primary dimensions but copies each component using its actual plane dimensions. The oversized alpha plane is therefore copied beyond the allocation, causing an out-of-bounds write; the inverse size mismatch can also produce an out-of-bounds read. This issue is fixed in version 1.23.1."}],"affected":[{"vendor":"strukturag","product":"libheif","versions":[{"version":"< 1.23.1","status":"affected"}]}],"references":[{"url":"https://github.com/strukturag/libheif/security/advisories/GHSA-xpw3-9rhw-482x","name":"https://github.com/strukturag/libheif/security/advisories/GHSA-xpw3-9rhw-482x","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/strukturag/libheif/commit/ac5521ad50399885de96bb6a0733a5d2442740f9","name":"https://github.com/strukturag/libheif/commit/ac5521ad50399885de96bb6a0733a5d2442740f9","tags":["x_refsource_MISC"]},{"url":"https://github.com/strukturag/libheif/releases/tag/v1.23.1","name":"https://github.com/strukturag/libheif/releases/tag/v1.23.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"LOW","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","description":"CWE-125: Out-of-bounds Read","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"CWE-787: Out-of-bounds Write","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-18T21:21:32.182Z"},"source":{"advisory":"GHSA-xpw3-9rhw-482x","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/strukturag/libheif/security/advisories/GHSA-xpw3-9rhw-482x","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-21T19:08:04.109354Z","id":"CVE-2026-62291","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-21T19:11:12.114Z"}}]}}}