{"id":"CVE-2026-89778","revision":"390096ebe7a149e0b7faad50706bda61","records":[{"revision":"390096ebe7a149e0b7faad50706bda61","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89778","aliases":[],"title":"isofs: fix out-of-bounds page array access on empty zisofs block","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nisofs: fix out-of-bounds page array access on empty zisofs block\n\nzisofs_uncompress_block()'s empty-block fast path returns\npcount << PAGE_SHIFT, ignoring the incoming poffset, unlike the\ndecompression path which returns bytes produced relative to poffset.\nzisofs_fill_pages() uses that return to advance its page cursor, so when\nthe zisofs block size is below PAGE_SIZE and a sub-page block leaves\npoffset partway into a page, a following empty block over-counts and\nadvances pages[] one element past its end, after which\n\"if (poffset && *pages)\" reads pages[1] out of bounds. rock.c only\nrejects a block-size shift > 17, so a crafted \"ZF\" Rock Ridge record can\nset it below PAGE_SHIFT; the bug is reached by an ordinary read() of a\ncompressed file on such a mounted ISO9660 image.\n\nReturn the byte count relative to poffset and zero only\n[poffset, PAGE_SIZE) of the first page, matching the decompression path.\nThe page-aligned case (poffset == 0) is unaffected.\n\n BUG: KASAN: slab-out-of-bounds in zisofs_read_folio (fs/isofs/compress.c:290)\n Read of size 8 at addr ffff88800f5eac48 by task exploit/142\n zisofs_read_folio (fs/isofs/compress.c:290)\n read_pages (mm/readahead.c:184)\n ...\n filemap_read (mm/filemap.c:2814)\n vfs_read (fs/read_write.c:574)\n __x64_sys_pread64 (fs/read_write.c:769)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n The buggy address is located 0 bytes to the right of the\n allocated 8-byte region in the kmalloc-8 cache","state":0,"publishedAt":"2026-09-16T08:48:18.407+00:00","modifiedAt":"2026-10-19T08:52:30.51+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"fs/isofs/compress.c\"\n ],\n \"versions\": [\n {\n \"version\": \"59bc055211b8d266ab6089158058bf8268e02006\",\n \"lessThan\": \"8b994ac5778a725982fd6a8a3afcaa068d4a93e3\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"59bc055211b8d266ab6089158058bf8268e02006\",\n \"lessThan\": \"ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"59bc055211b8d266ab6089158058bf8268e02006\",\n \"lessThan\": \"85904076cece72ee3194646ad7ac8e6659d999aa\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"59bc055211b8d266ab6089158058bf8268e02006\",\n \"lessThan\": \"f03425dcbe04aec3c27b9917e97d7d23a2908dda\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"59bc055211b8d266ab6089158058bf8268e02006\",\n \"lessThan\": \"cd616aa0449a772a6956abf03358f0ff31720580\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"59bc055211b8d266ab6089158058bf8268e02006\",\n \"lessThan\": \"9c6eace8d07e90f038c89eb3b756d65a7e259d48\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"59bc055211b8d266ab6089158058bf8268e02006\",\n \"lessThan\": \"68d4d3e78150c7ed7d1195af63ad1e6ace30c661\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"fs/isofs/compress.c\"\n ],\n \"versions\": [\n {\n \"version\": \"2.6.33\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"2.6.33\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.221\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.188\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.157\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.110\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.52\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.6\",\n \"lessThanOrEqual\": \"7.2.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.3\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/8b994ac5778a725982fd6a8a3afcaa068d4a93e3","https://git.kernel.org/stable/c/ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a","https://git.kernel.org/stable/c/85904076cece72ee3194646ad7ac8e6659d999aa","https://git.kernel.org/stable/c/f03425dcbe04aec3c27b9917e97d7d23a2908dda","https://git.kernel.org/stable/c/cd616aa0449a772a6956abf03358f0ff31720580","https://git.kernel.org/stable/c/9c6eace8d07e90f038c89eb3b756d65a7e259d48","https://git.kernel.org/stable/c/68d4d3e78150c7ed7d1195af63ad1e6ace30c661"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89778","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89778","identifiers":["CVE-2026-89778"]},"retained":false,"historicalAffected":[]}],"coverage":[]}