# CVE-2023-53783: linux: In the Linux kernel, the following vulnerability has been resolved: blk-iocost: fix divide by 0 error in calc_lcoefs... CVE-2023-53783 is fixed in 20 products on 1 platform, first by ALAS2023-2023-138, released March 20, 2023. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2023-53783 - Priority: High - CVSS: n/a (important) - EPSS: 0.0021 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Mar 20, 2023 ## Description 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: 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 ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | bpftool-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-devel amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-headers amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-libbpf amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-libbpf-devel amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-libbpf-static amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-livepatch-6.1.19-30.43 amzn 2023 | 1.0-0.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-tools amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-tools-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-tools-devel amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | linux Debian 12.15 (bookworm) | 6.1.20-1 | [DEBIAN-CVE-2023-53783](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53783.md) | Dec 9, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.1.20-1 | [DEBIAN-CVE-2023-53783](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53783.md) | Dec 9, 2025 | | Linux | linux Debian 14 | 6.1.20-1 | [DEBIAN-CVE-2023-53783](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53783.md) | Dec 9, 2025 | | Linux | perf amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | perf-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | python3-perf amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | python3-perf-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | --- Data as of 2026-11-08T06:59:42Z UTC. 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