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CVE-2025-40237

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : 6.13, <950b604384fd75d62e860bec7135b2b62eb4d508, <=6.12.*, <3f307a9f7a7a2822e38ac451b73e2244e7279496, <6.6.115, 0, <6.13, 6.18, <=6.6.*, 6.6.73, c45beebfde34aa71afbc48b2c54cdda623515037, 6.6.72, <6.6.73, 6.17.6, 6.6.115, <d1894bc542becb0fda61e7e513b09523cab44030, <=*, <6.12.56, 3c7c90274ae339e1ad443c9be1c67a20b80b9c76, 6.12.10, <=6.17.*, <a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a, a1a541fbfa7e97c1100144db34b57553d7164ce5, f0c0ac84de17c37e6e84da65fb920f91dada55ad, 6.12.56, 6.6.74, <bc1c6b803e14ea2b8f7e33b7164013f666ceb656

Description

In the Linux kernel, the following vulnerability has been resolved: fs/notify: call exportfs_encode_fid with s_umount Calling intotify_show_fdinfo() on fd watching an overlayfs inode, while the overlayfs is being unmounted, can lead to dereferencing NULL ptr. This issue was found by syzkaller. Race Condition Diagram: Thread 1 Thread 2 -------- -------- generic_shutdown_super() shrink_dcache_for_umount sb->s_root = NULL | | vfs_read() | inotify_fdinfo() | * inode get from mark * | show_mark_fhandle(m, inode) | exportfs_encode_fid(inode, ..) | ovl_encode_fh(inode, ..) | ovl_check_encode_origin(inode) | * deref i_sb->s_root * | | v fsnotify_sb_delete(sb) Which then leads to: [ 32.133461] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [ 32.134438] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] [ 32.135032] CPU: 1 UID: 0 PID: 4468 Comm: systemd-coredum Not tainted 6.17.0-rc6 #22 PREEMPT(none) <snip registers, unreliable trace> [ 32.143353] Call Trace: [ 32.143732] ovl_encode_fh+0xd5/0x170 [ 32.144031] exportfs_encode_inode_fh+0x12f/0x300 [ 32.144425] show_mark_fhandle+0xbe/0x1f0 [ 32.145805] inotify_fdinfo+0x226/0x2d0 [ 32.146442] inotify_show_fdinfo+0x1c5/0x350 [ 32.147168] seq_show+0x530/0x6f0 [ 32.147449] seq_read_iter+0x503/0x12a0 [ 32.148419] seq_read+0x31f/0x410 [ 32.150714] vfs_read+0x1f0/0x9e0 [ 32.152297] ksys_read+0x125/0x240 IOW ovl_check_encode_origin derefs inode->i_sb->s_root, after it was set to NULL in the unmount path. Fix it by protecting calling exportfs_encode_fid() from show_mark_fhandle() with s_umount lock. This form of fix was suggested by Amir in [1]. [1]: https://lore.kernel.org/all/CAOQ4uxhbDwhb+2Brs1UdkoF0a3NSdBAOQPNfEHjahrgoKJpLEw@mail.gmail.com/

Gravité et risque d'exploitation

CVE-2025-40237 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.20 %, ce qui la place devant 9.3 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions 6.13, <950b604384fd75d62e860bec7135b2b62eb4d508, <=6.12.*, <3f307a9f7a7a2822e38ac451b73e2244e7279496, <6.6.115, 0, <6.13, 6.18, <=6.6.*, 6.6.73, c45beebfde34aa71afbc48b2c54cdda623515037, 6.6.72, <6.6.73, 6.17.6, 6.6.115, <d1894bc542becb0fda61e7e513b09523cab44030, <=*, <6.12.56, 3c7c90274ae339e1ad443c9be1c67a20b80b9c76, 6.12.10, <=6.17.*, <a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a, a1a541fbfa7e97c1100144db34b57553d7164ce5, f0c0ac84de17c37e6e84da65fb920f91dada55ad, 6.12.56, 6.6.74, <bc1c6b803e14ea2b8f7e33b7164013f666ceb656) 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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