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CVE-2026-89778

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.7%
Linux•Linux•Versions : <=6.1.*, <f03425dcbe04aec3c27b9917e97d7d23a2908dda, <=6.12.*, 5.15.221, 0, <cd616aa0449a772a6956abf03358f0ff31720580, 6.1.188, 6.18.52, <=6.6.*, 6.6.157, <8b994ac5778a725982fd6a8a3afcaa068d4a93e3, 59bc055211b8d266ab6089158058bf8268e02006, <2.6.33, 7.2.6, 2.6.33, <=6.18.*, 6.12.110, <=7.2.*, <68d4d3e78150c7ed7d1195af63ad1e6ace30c661, <85904076cece72ee3194646ad7ac8e6659d999aa, <=*, <=5.15.*, <9c6eace8d07e90f038c89eb3b756d65a7e259d48, <ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a, 7.3

Description

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

Gravité et risque d'exploitation

CVE-2026-89778 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.70 %, ce qui la place devant 52.1 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <f03425dcbe04aec3c27b9917e97d7d23a2908dda, <=6.12.*, 5.15.221, 0, <cd616aa0449a772a6956abf03358f0ff31720580, 6.1.188, 6.18.52, <=6.6.*, 6.6.157, <8b994ac5778a725982fd6a8a3afcaa068d4a93e3, 59bc055211b8d266ab6089158058bf8268e02006, <2.6.33, 7.2.6, 2.6.33, <=6.18.*, 6.12.110, <=7.2.*, <68d4d3e78150c7ed7d1195af63ad1e6ace30c661, <85904076cece72ee3194646ad7ac8e6659d999aa, <=*, <=5.15.*, <9c6eace8d07e90f038c89eb3b756d65a7e259d48, <ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a, 7.3) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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