minix: avoid overflow in bitmap block count calculation
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: minix: avoid overflow in bitmap block count calculation minix_check_superblock() uses minix_blocks_needed() to verify that the on-disk imap and zmap block counts are large enough for the advertised inode and zone counts. The helper currently performs DIV_ROUND_UP() in unsigned int arithmetic. A Minix v3 image can set s_ninodes or s_zones near UINT_MAX so the addition inside DIV_ROUND_UP() wraps to zero. That makes a zero imap/zmap block count look valid, after which minix_fill_super() can dereference s_imap[0] or s_zmap[0] even though no bitmap buffers were allocated. Impact: mounting a crafted Minix v3 image whose s_ninodes or s_zones is near UINT_MAX makes minix_check_superblock() accept a zero bitmap-block count and minix_fill_super() dereference s_imap[0]/s_zmap[0], panicking the kernel. The divisor is the bitmap capacity in bits, blocksize * 8, which is always a power of two: minix_fill_super() obtains the block size through sb_set_blocksize(), and blk_validate_block_size() rejects any size that is not a power of two. Use DIV_ROUND_UP_POW2(), which divides before adding the round-up term and so cannot overflow for a power-of-two divisor.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.6.128 to before 6.6.145; 6.12.75 to before 6.12.97; 6.18.16 to before 6.18.40; 5.10.252 to before 5.11; 5.15.202 to before 5.16; 6.1.165 to before 6.2; 6.19.6 to before 6.20 | 6.6.145, 6.12.97, 6.18.40, 5.11, 5.16, 6.2, 6.20 | Patch available | CNA |
| Linux | Linux | 7.0 and later | 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 6.6.128 to before 6.6.145; 6.12.75 to before 6.12.97; 6.18.16 to before 6.18.40; 5.10.252 to before 5.11; 5.15.202 to before 5.16; 6.1.165 to before 6.2; 6.19.6 to before 6.20 Fixed in 6.6.145, 6.12.97, 6.18.40, 5.11, 5.16, 6.2, 6.20 Patch available CNA
- Linux VendorLinux Affected 7.0 and later Fixed in 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.145, 6.12.97, 6.18.40, 5.11, 5.16, 6.2, 6.20
- Fix · CNA Linux (Linux) Fixed in 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2
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 |
Not affected: 4 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-72369
- 2026-10-03 Alias added: GHSA-37g9-2p78-fr5w
References
Other 5
- https://git.kernel.org/stable/c/a11ebaab50d27d6c4c78506f84ff36452e0b901d
- https://git.kernel.org/stable/c/959c95340a9e19cd333b4c18935fdeecbb2f319d
- https://git.kernel.org/stable/c/abe3536a4bedcc43de80b6d4d7e3d57e9ba382a5
- https://git.kernel.org/stable/c/8a29e60e2176b02e04f8737c8b32b696230eb0c5
- https://git.kernel.org/stable/c/fb3e566cafc38fe3ba35e6843a2d529a3748870c
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Sources
- CVE-2026-72369 · CVE Program
- CVE-2026-72369 · NVD
- FIRST EPSS
- GHSA-37g9-2p78-fr5w · GitHub Advisory Database · CC BY 4.0
- CVE-2026-72369 · Red Hat security data · CC BY 4.0
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