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CVE-2026-89696: Linux

7.5

CVSS 3.1

Няма данни

Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

Няма потвърждение

Атакува се

Няма данни

Време до експлоатация

Атакува се по мрежата, без особени условия, без вход и без действие от потребителя.

    Описание

    Оригинално описание

    In the Linux kernel, the following vulnerability has been resolved: nfsd: block non-SAVEFH ops after FOREIGN PUTFH to prevent NULL deref When CONFIG_NFSD_V4_2_INTER_SSC is enabled, nfsd4_putfh() can return success with fh_dentry and fh_export both NULL if fh_verify() returns nfserr_stale and putfh->no_verify is true. The NFSD4_FH_FOREIGN flag is set, but the compound dispatch loop only uses this flag to bypass the nfserr_nofilehandle check -- it does not prevent subsequent ops from running with a NULL fh_dentry. A remote client can exploit this by crafting a COMPOUND that includes an inter-SSC COPY (which causes check_if_stalefh_allowed() to set no_verify=true on the saved PUTFH) with an additional op inserted between the source PUTFH and SAVEFH. For example, SETATTR calls fh_want_write() which dereferences fh_export->ex_path.mnt without calling fh_verify() first, causing a NULL pointer dereference in the nfsd kthread. Fix this by gating the dispatch loop: when NFSD4_FH_FOREIGN is set and fh_dentry is NULL, only OP_SAVEFH (needed for the inter-SSC flow) and ops with ALLOWED_WITHOUT_FH (which don't need a resolved filehandle) may proceed. All other ops receive nfserr_stale, per RFC 7862 Section 15.2.3 which specifies that foreign filehandle validation is deferred to the consuming operation and NFS4ERR_STALE returned at that point.

    Засегнати продукти

    • Linux Linux: b9e8638e3d9ed8334f1f7071e081860aac37e83e преди ffdc844e673d2bcb2af8c8c3eef8cdea59d0bf32; b9e8638e3d9ed8334f1f7071e081860aac37e83e преди 00c84f4eec715e501efc080a5670114189e42507; b9e8638e3d9ed8334f1f7071e081860aac37e83e преди 2d9846fd1c767920fddd4bde30eb35cd2969df13; b9e8638e3d9ed8334f1f7071e081860aac37e83e преди 977e6f006a7a3ffc4216ae6034f768f8de6fd138; b9e8638e3d9ed8334f1f7071e081860aac37e83e преди 35f248bd40b47b229d4999581df45b97daadd977; b9e8638e3d9ed8334f1f7071e081860aac37e83e преди 311f7d926630940650447cbd1c932b076b40a6c4; b9e8638e3d9ed8334f1f7071e081860aac37e83e преди bf4d338dc8625d70c7f2cb0657d66851a7ac9154; b9e8638e3d9ed8334f1f7071e081860aac37e83e преди c59738a00aa51b16adc1b5ceb7c80877168efb4d
    • Linux Linux: 5.6; преди 5.6; 5.10.270 до 5.10.*; 5.15.221 до 5.15.*; 6.1.188 до 6.1.*; 6.6.157 до 6.6.*; 6.12.109 до 6.12.*; 6.18.50 до 6.18.*; 7.2.4 до 7.2.*; от 7.3 нататък

    История

    • 11 септември 2026 Публикувано

    Други уязвимости в Linux Linux

    Първоизточници

    CVE-2026-89696: Linux | freedomonline.bg