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CVE-2023-53783· NVD / CVE Program· CNA Linux

blk-iocost: fix divide by 0 error in calc_lcoefs()

In the Linux kernel, the following vulnerability has been resolved: blk-iocost: fix divide by 0 error in calc_lcoefs() echo max of u64 to cost.model can cause divide by 0 error. # echo 8:0 rbps=18446744073709551615 > /sys/fs/cgroup/io.cost.model divide error: 0000 [#1] PREEMPT SMP RIP: 0010:calc_lcoefs+0x4c/0xc0 Call Trace: <TASK> ioc_refresh_params+0x2b3/0x4f0 ioc_cost_model_write+0x3cb/0x4c0 ? _copy_from_iter+0x6d/0x6c0 ? kernfs_fop_write_iter+0xfc/0x270 cgroup_file_write+0xa0/0x200 kernfs_fop_write_iter+0x17d/0x270 vfs_write+0x414/0x620 ksys_write+0x73/0x160 __x64_sys_write+0x1e/0x30 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd calc_lcoefs() uses the input value of cost.model in DIV_ROUND_UP_ULL, overflow would happen if bps plus IOC_PAGE_SIZE is greater than ULLONG_MAX, it can cause divide by 0 error. Fix the problem by setting basecost

—No exploit Fix available
Published
Dec 8, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 9th percentile
CWE
—
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Action score

0

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Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

Affected systems

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.4affected
    • 7caa47151ab2e644dd221f741ec7578d9532c9a3 and later · before 9e8bf9f95f7a299fa9ea45b678d001806ad5e12caffected · git
    • 7caa47151ab2e644dd221f741ec7578d9532c9a3 and later · before 6e291810fe83a384700eb24a1f714966391ed562affected · git
    • 7caa47151ab2e644dd221f741ec7578d9532c9a3 and later · before 3538ade9d8c2ba41088e395de916f2599fadba8faffected · git
    • 7caa47151ab2e644dd221f741ec7578d9532c9a3 and later · before bf8eb1fd6110871e6232e8e7efe399276ef7e6f6affected · git
    • 7caa47151ab2e644dd221f741ec7578d9532c9a3 and later · before b96d7b4a9745fbd0c8384608ceb1f50415e862faaffected · git
    • 7caa47151ab2e644dd221f741ec7578d9532c9a3 and later · before 984af1e66b4126cf145153661cc24c213e2ec231affected · git
    • before 5.4not affected · semver
    • 5.4.235 and later · up to and including 5.4.*not affected · semver
    • 5.10.173 and later · up to and including 5.10.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.20-16.1.20-1

Same product

linux: all records

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3538ade9d8c2ba41088e395de916f2599fadba8fVendor (CNA)
Linux Linux6e291810fe83a384700eb24a1f714966391ed562Vendor (CNA)
Linux Linux984af1e66b4126cf145153661cc24c213e2ec231Vendor (CNA)
Linux Linux9e8bf9f95f7a299fa9ea45b678d001806ad5e12cVendor (CNA)
Linux Linuxb96d7b4a9745fbd0c8384608ceb1f50415e862faVendor (CNA)
Linux Linuxbf8eb1fd6110871e6232e8e7efe399276ef7e6f6Vendor (CNA)
debian:linux6.1.20-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

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Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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