{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89778","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.765Z","datePublished":"2026-09-16T08:48:18.407Z","dateUpdated":"2026-09-16T14:38:29.867Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-16T14:38:29.867Z"},"descriptions":[{"lang":"en","value":"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"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - isofs assigns s_export_op to isofs_export_ops; nfsd_read then nfsd_iter_read (vfs_iocb_iter_read) and ksmbd_vfs_read (kernel_read) perform VFS reads that reach generic_file_read_iter, filemap_read, and zisofs_read_folio, so a remote NFS or SMB client can trigger the bug on a host exporting a crafted ISO9660 image.\nAC:L - The attacker fully controls the Rock Ridge ZF parms (rock.c only rejects block_shift > 17) and the zisofs block pointer table; a block_shift below PAGE_SHIFT plus a nonempty sub-page block followed by an empty block (block_start==block_end) deterministically over-advances pages[] with no race.\nPR:N - A remote NFS or SMB client needs only read access to an exported iso9660 tree; AUTH_SYS media-server exports commonly require no host credentials, and compressed regular files default to S_IRUGO. No CAP_SYS_ADMIN on the victim host is required on the read path.\nUI:N - Once an iso9660 volume containing the crafted zisofs file is exported, the NFS or SMB server processes the client's READ automatically; no separate victim must open a file or click a dialog at attack time beyond that pre-existing export.\nS:U - The slab out-of-bounds pointer load and any memzero_page or SetPageUptodate side effects remain inside the host kernel; this is not a VM escape, IOMMU/DMA bypass, or other cross-authority boundary.\nC:H - zisofs_fill_pages loads an 8-byte pointer from one slot past a kmalloc-8 pages[] allocation and may treat adjacent heap data as a struct page. With heap grooming this memory corruption can be turned into a kernel information-disclosure primitive, so confidentiality impact is High.\nI:H - When the out-of-bounds pointer is non-NULL, memzero_page() writes zeros through kmap_local_page() of the forged page and SetPageUptodate() corrupts page flags, yielding a kernel write primitive against attacker-groomed heap or page objects that can be chained to control-flow hijack.\nA:H - KASAN reports a slab-out-of-bounds read in zisofs_read_folio; feeding a non-page pointer to kmap_local_page or memzero_page oopses or panics the kernel, and the attacker can repeat the NFS, SMB, or local read at will."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/isofs/compress.c"],"versions":[{"version":"59bc055211b8d266ab6089158058bf8268e02006","lessThan":"8b994ac5778a725982fd6a8a3afcaa068d4a93e3","status":"affected","versionType":"git"},{"version":"59bc055211b8d266ab6089158058bf8268e02006","lessThan":"ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a","status":"affected","versionType":"git"},{"version":"59bc055211b8d266ab6089158058bf8268e02006","lessThan":"85904076cece72ee3194646ad7ac8e6659d999aa","status":"affected","versionType":"git"},{"version":"59bc055211b8d266ab6089158058bf8268e02006","lessThan":"f03425dcbe04aec3c27b9917e97d7d23a2908dda","status":"affected","versionType":"git"},{"version":"59bc055211b8d266ab6089158058bf8268e02006","lessThan":"cd616aa0449a772a6956abf03358f0ff31720580","status":"affected","versionType":"git"},{"version":"59bc055211b8d266ab6089158058bf8268e02006","lessThan":"9c6eace8d07e90f038c89eb3b756d65a7e259d48","status":"affected","versionType":"git"},{"version":"59bc055211b8d266ab6089158058bf8268e02006","lessThan":"68d4d3e78150c7ed7d1195af63ad1e6ace30c661","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/isofs/compress.c"],"versions":[{"version":"2.6.33","status":"affected"},{"version":"0","lessThan":"2.6.33","status":"unaffected","versionType":"semver"},{"version":"5.15.221","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.110","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.52","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.6","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.33","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.33","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.33","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.33","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.33","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.33","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.33","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/8b994ac5778a725982fd6a8a3afcaa068d4a93e3"},{"url":"https://git.kernel.org/stable/c/ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a"},{"url":"https://git.kernel.org/stable/c/85904076cece72ee3194646ad7ac8e6659d999aa"},{"url":"https://git.kernel.org/stable/c/f03425dcbe04aec3c27b9917e97d7d23a2908dda"},{"url":"https://git.kernel.org/stable/c/cd616aa0449a772a6956abf03358f0ff31720580"},{"url":"https://git.kernel.org/stable/c/9c6eace8d07e90f038c89eb3b756d65a7e259d48"},{"url":"https://git.kernel.org/stable/c/68d4d3e78150c7ed7d1195af63ad1e6ace30c661"}],"title":"isofs: fix out-of-bounds page array access on empty zisofs block","x_generator":{"engine":"bippy-1.2.0"}}}}