In the Linux kernel, the following vulnerability has been resolved:
ext4: fix potential null deref in ext4_mb_init()
In ext4_mb_init(), ext4_mb_avg_fragment_size_destroy() may be called when sbi->s_mb_avg_fragment_size remains uninitialized (e.g., if groupinfo slab cache allocation fails). Since ext4_mb_avg_fragment_size_destroy() lacks null pointer checking, this leads to a null pointer dereference.
================================================================== EXT4-fs: no memory for groupinfo slab cache BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: Oops: 0002 [#1] SMP PTI CPU:2 UID: 0 PID: 87 Comm:mount Not tainted 6.17.0-rc2 #1134 PREEMPT(none) RIP: 0010:_raw_spin_lock_irqsave+0x1b/0x40 Call Trace: <TASK> xa_destroy+0x61/0x130 ext4_mb_init+0x483/0x540 __ext4_fill_super+0x116d/0x17b0 ext4_fill_super+0xd3/0x280 get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x29/0xd0 do_new_mount+0x197/0x300 __x64_sys_mount+0x116/0x150 do_syscall_64+0x50/0x1c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e ==================================================================
Therefore, add necessary null check to ext4_mb_avg_fragment_size_destroy() to prevent this issue. The same fix is also applied to ext4_mb_largest_free_orders_destroy().
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Nov 12, 2025 |
| Ubuntu | — | Upgrade linux-image-6.17.0-1007-awsUpgrade linux-image-6.17.0-14-genericUpgrade linux-image-6.17.0-14-generic-64kUpgrade linux-image-oracle-6.17Upgrade linux-image-6.17.0-1007-gcp-64kUpgrade linux-image-oracleUpgrade linux-image-oracle-64k-6.17Upgrade linux-image-gcp-6.17Upgrade linux-image-virtualUpgrade linux-image-gcp-64k-6.17Upgrade linux-image-realtimeUpgrade linux-image-awsUpgrade linux-image-generic-6.17Upgrade linux-image-6.17.0-1007-aws-64kUpgrade linux-image-oem-6.17Upgrade linux-image-6.17.0-1011-oemUpgrade linux-image-6.17.0-1007-gcpUpgrade linux-image-6.17.0-1008-raspiUpgrade linux-image-realtime-6.17Upgrade linux-image-gcp-64kUpgrade linux-image-oracle-64kUpgrade linux-image-generic-64kUpgrade linux-image-generic-64k-6.17Upgrade linux-image-azure-6.17Upgrade linux-image-aws-6.17Upgrade linux-image-6.17.0-1007-oracle-64kUpgrade linux-image-genericUpgrade linux-image-azureUpgrade linux-image-gcpUpgrade linux-image-raspiUpgrade linux-image-aws-64k-6.17Upgrade linux-image-6.17.0-1006-realtimeUpgrade linux-image-6.17.0-1007-oracleUpgrade linux-image-aws-64kUpgrade linux-image-virtual-6.17Upgrade linux-image-raspi-6.17Upgrade linux-image-6.17.0-1008-azure | Feb 13, 2026 | Feb 12, 2026 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub