ext4: add reserved GDT blocks check
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 5 fixed, 4 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-476.
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: add reserved GDT blocks check We capture a NULL pointer issue when resizing a corrupt ext4 image which is freshly clear resize_inode feature (not run e2fsck). It could be simply reproduced by following steps. The problem is because of the resize_inode feature was cleared, and it will convert the filesystem to meta_bg mode in ext4_resize_fs(), but the es->s_reserved_gdt_blocks was not reduced to zero, so could we mistakenly call reserve_backup_gdb() and passing an uninitialized resize_inode to it when adding new group descriptors. mkfs.ext4 /dev/sda 3G tune2fs -O ^resize_inode /dev/sda #forget to run requested e2fsck mount /dev/sda /mnt resize2fs /dev/sda 8G ======== BUG: kernel NULL pointer dereference, address: 0000000000000028 CPU: 19 PID: 3243 Comm: resize2fs Not tainted 5.18.0-rc7-00001-gfde086c5ebfd #748 ... RIP: 0010:ext4_flex_group_add+0xe08/0x2570 ... Call Trace: <TASK> ext4_resize_fs+0xbec/0x1660 __ext4_ioctl+0x1749/0x24e0 ext4_ioctl+0x12/0x20 __x64_sys_ioctl+0xa6/0x110 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f2dd739617b ======== The fix is simple, add a check in ext4_resize_begin() to make sure that the es->s_reserved_gdt_blocks is zero when the resize_inode feature is disabled.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.7 and later | 4.9.320, 4.14.285, 4.19.249, 5.4.200, 5.10.124, 5.15.49, 5.18.6, 5.19 | Patch available | CNA |
- Linux VendorLinux Affected 3.7 and later Fixed in 4.9.320, 4.14.285, 4.19.249, 5.4.200, 5.10.124, 5.15.49, 5.18.6, 5.19 Patch available CNA
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | before 4.9.320; 4.10 to before 4.14.285; 4.15 to before 4.19.249; 4.20 to before 5.4.200; 5.5 to before 5.10.124; 5.11 to before 5.15.49; 5.16 to before 5.18.6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.19:rc1:*:*:*:*:*:* | 5.19 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.19:rc2:*:*:*:*:*:* | 5.19 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions before 4.9.320; 4.10 to before 4.14.285; 4.15 to before 4.19.249; 4.20 to before 5.4.200; 5.5 to before 5.10.124; 5.11 to before 5.15.49; 5.16 to before 5.18.6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.19:rc1:*:*:*:*:*:* Versions 5.19 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.19:rc2:*:*:*:*:*:* Versions 5.19 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.9.320, 4.14.285, 4.19.249, 5.4.200, 5.10.124, 5.15.49, 5.18.6, 5.19
Red Hat 2 advisories
- RHSA-2022:8267 Released 2022-11-15 · Red Hat rating Moderatekernel security, bug fix, and enhancement update
- Red Hat CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-162.6.1.el9_1
- Red Hat Enterprise Linux AppStream (v. 9) kernel-debug-devel-5.14.0-162.6.1.el9_1, kernel-debug-devel-matched-5.14.0-162.6.1.el9_1, kernel-devel-5.14.0-162.6.1.el9_1 +5
- Red Hat Enterprise Linux BaseOS (v. 9) bpftool-5.14.0-162.6.1.el9_1, kernel-5.14.0-162.6.1.el9_1, kernel-abi-stablelists-5.14.0-162.6.1.el9_1 +14
- RHSA-2022:7683 Released 2022-11-08 · Red Hat rating Moderatekernel security, bug fix, and enhancement update
- Red Hat CodeReady Linux Builder (v. 8) kernel-tools-libs-devel-4.18.0-425.3.1.el8
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-425.3.1.el8, kernel-4.18.0-425.3.1.el8, kernel-abi-stablelists-4.18.0-425.3.1.el8 +19
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat CodeReady Linux Builder (v. 8) | Fixed | RHSA-2022:7683 |
| Red Hat CodeReady Linux Builder (v. 9) | Fixed | RHSA-2022:8267 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2022:8267 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2022:7683 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2022:8267 |
Not affected: 1 product
- Red Hat Enterprise Linux 10
Timeline
- 2026-10-02 Threatist record created from CVE-2022-49707
- 2026-10-03 Alias added: GHSA-gcmg-mgh2-gvc3
References
Patch 8
- https://git.kernel.org/stable/c/0dc2fca8e4f9ac4a40e8424a10163369cca0cc06
- https://git.kernel.org/stable/c/7c921328ac760bba780bdace41f4cd045f7f1405
- https://git.kernel.org/stable/c/b9747263b13e5290ac4d63bec47e38f701303cad
- https://git.kernel.org/stable/c/fba54289176702a7caac0b64738406775817f451
- https://git.kernel.org/stable/c/bfd004a1d3a062aac300523d406ac1f3e5f1a82c
- https://git.kernel.org/stable/c/33b1bba31f4c784d33d2c2517964bdccdc9204cd
- https://git.kernel.org/stable/c/af75c481a2e45e70f62f5942c93695e95bf7bd21
- https://git.kernel.org/stable/c/b55c3cd102a6f48b90e61c44f7f3dda8c290c694
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Sources
- CVE-2022-49707 · CVE Program
- CVE-2022-49707 · NVD
- FIRST EPSS
- GHSA-gcmg-mgh2-gvc3 · GitHub Advisory Database · CC BY 4.0
- CVE-2022-49707 · Red Hat security data · CC BY 4.0
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