CVE-2026-89778

{"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": "2026-10-19T08:52:30.510Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:52:30.510Z"}, "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", "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"}]}]}], "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"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/isofs/compress.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "8b994ac5778a725982fd6a8a3afcaa068d4a93e3", "status": "affected", "version": "59bc055211b8d266ab6089158058bf8268e02006", "versionType": "git"}, {"lessThan": "ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a", "status": "affected", "version": "59bc055211b8d266ab6089158058bf8268e02006", "versionType": "git"}, {"lessThan": "85904076cece72ee3194646ad7ac8e6659d999aa", "status": "affected", "version": "59bc055211b8d266ab6089158058bf8268e02006", "versionType": "git"}, {"lessThan": "f03425dcbe04aec3c27b9917e97d7d23a2908dda", "status": "affected", "version": "59bc055211b8d266ab6089158058bf8268e02006", "versionType": "git"}, {"lessThan": "cd616aa0449a772a6956abf03358f0ff31720580", "status": "affected", "version": "59bc055211b8d266ab6089158058bf8268e02006", "versionType": "git"}, {"lessThan": "9c6eace8d07e90f038c89eb3b756d65a7e259d48", "status": "affected", "version": "59bc055211b8d266ab6089158058bf8268e02006", "versionType": "git"}, {"lessThan": "68d4d3e78150c7ed7d1195af63ad1e6ace30c661", "status": "affected", "version": "59bc055211b8d266ab6089158058bf8268e02006", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/isofs/compress.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "2.6.33"}, {"lessThan": "2.6.33", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.221", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.188", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.157", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.110", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.52", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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"}], "id": "CVE-2026-89778", "lastModified": "2026-10-19T09:18:21.100", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-16T09:17:08.253", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/68d4d3e78150c7ed7d1195af63ad1e6ace30c661"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/85904076cece72ee3194646ad7ac8e6659d999aa"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8b994ac5778a725982fd6a8a3afcaa068d4a93e3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9c6eace8d07e90f038c89eb3b756d65a7e259d48"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/cd616aa0449a772a6956abf03358f0ff31720580"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f03425dcbe04aec3c27b9917e97d7d23a2908dda"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[59bc055211b8d266ab6089158058bf8268e02006,8b994ac5778a725982fd6a8a3afcaa068d4a93e3)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[59bc055211b8d266ab6089158058bf8268e02006,ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[59bc055211b8d266ab6089158058bf8268e02006,85904076cece72ee3194646ad7ac8e6659d999aa)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[59bc055211b8d266ab6089158058bf8268e02006,f03425dcbe04aec3c27b9917e97d7d23a2908dda)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[59bc055211b8d266ab6089158058bf8268e02006,cd616aa0449a772a6956abf03358f0ff31720580)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[59bc055211b8d266ab6089158058bf8268e02006,9c6eace8d07e90f038c89eb3b756d65a7e259d48)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[59bc055211b8d266ab6089158058bf8268e02006,68d4d3e78150c7ed7d1195af63ad1e6ace30c661)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "2.6.33"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,2.6.33)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.15.221,5.16.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.188,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.157,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.110,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.52,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.6,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-16T12:15:07.702243+00:00", "updated": "2026-09-20T04:45:17.015374+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-125"]}