Answer in brief
CVE-2026-89778 records a Critical severity (CVSS 9.8) vulnerability in isofs: fix out-of-bounds page array access on empty zisofs block. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=59bc055211b8d266ab6089158058bf8268e02006 <8b994ac5778a725982fd6a8a3afcaa068d4a93e3 || >=59bc055211b8d266ab6089158058bf8268e02006 <ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a || >=59bc055211b8d266ab6089158058bf8268e02006 <85904076cece72ee3194646ad7ac8e6659d999aa || >=59bc055211b8d266ab6089158058bf8268e02006 <f03425dcbe04aec3c27b9917e97d7d23a2908dda || >=59bc055211b8d266ab6089158058bf8268e02006 <cd616aa0449a772a6956abf03358f0ff31720580 || >=59bc055211b8d266ab6089158058bf8268e02006 <9c6eace8d07e90f038c89eb3b756d65a7e259d48 || >=59bc055211b8d266ab6089158058bf8268e02006 <68d4d3e78150c7ed7d1195af63ad1e6ace30c661 | 8b994ac5778a725982fd6a8a3afcaa068d4a93e3, ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a, 85904076cece72ee3194646ad7ac8e6659d999aa, f03425dcbe04aec3c27b9917e97d7d23a2908dda, cd616aa0449a772a6956abf03358f0ff31720580, 9c6eace8d07e90f038c89eb3b756d65a7e259d48, 68d4d3e78150c7ed7d1195af63ad1e6ace30c661 |
| Linux/Linuxgeneric | 2.6.33 | Not reported |
Published upstream
Sep 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 16, 2026
In the Linux kernel, the following vulnerability has been resolved: isofs: fix out-of-bounds page array access on empty zisofs block zisofs_uncompress_block()'s empty-block fast path returns pcount << PAGE_SHIFT, ignoring the incoming poffset, unlike the decompression path which returns bytes produced relative to poffset. zisofs_fill_pages() uses that return to advance its page cursor, so when the zisofs block size is below PAGE_SIZE and a sub-page block leaves poffset partway into a page, a following empty block over-counts and advances pages[] one element past its end, after which "if (poffset && *pages)" reads pages[1] out of bounds. rock.c only rejects a block-size shift > 17, so a crafted "ZF" Rock Ridge record can set it below PAGE_SHIFT; the bug is reached by an ordinary read() of a compressed file on such a mounted ISO9660 image. Return the byte count relative to poffset and zero only [poffset, PAGE_SIZE) of the first page, matching the decompression path. The page-aligned case (poffset == 0) is unaffected. BUG: KASAN: slab-out-of-bounds in zisofs_read_folio (fs/isofs/compress.c:290) Read of size 8 at addr ffff88800f5eac48 by task exploit/142 zisofs_read_folio (fs/isofs/compress.c:290) read_pages (mm/readahead.c:184) ... filemap_read (mm/filemap.c:2814) vfs_read (fs/read_write.c:574) __x64_sys_pread64 (fs/read_write.c:769) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) The buggy address is located 0 bytes to the right of the allocated 8-byte region in the kmalloc-8 cache
Quoted source text, attributed separately from HOL analysis.