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CVE-2026-72369

HIGHCVSS 7.8/10EPSS 0.21%

Last modified

CVE-2026-72369 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.21%

11.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 2bb588cede1c1969e49c0a2822c8cb8b346b7682, < a11ebaab50d27d6c4c78506f84ff36452e0b901d; >= f57ccd4657c7f082dc47e5b9e18a883bb5f9118f, < 959c95340a9e19cd333b4c18935fdeecbb2f319d; >= 31fefc18096cdc5549cfa54964d90e0b3229aedc, < abe3536a4bedcc43de80b6d4d7e3d57e9ba382a5; >= 8c97a6ddc95690a938ded44b4e3202f03f15078c, < 8a29e60e2176b02e04f8737c8b32b696230eb0c5; >= 8c97a6ddc95690a938ded44b4e3202f03f15078c, < fb3e566cafc38fe3ba35e6843a2d529a3748870c; a051ecf5c5b0387840dc210413ed3bc7fbdaa69c; d791c544efd6b9c944b43cf7f502e5bcb02fb941; 66c7c239c65341f99ae388d4d53dc9df2bcb9925; 1efc128ee4adbc23e082715425ff895449d233bc; >= 6.6.128, < 6.6.145; >= 6.12.75, < 6.12.97; >= 6.18.16, < 6.18.40; >= 5.10.252, < 5.11; >= 5.15.202, < 5.16; >= 6.1.165, < 6.2; >= 6.19.6, < 6.20
LinuxLinux7.0

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-72369?
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.
How severe is CVE-2026-72369?
CVE-2026-72369 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-72369?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST