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NVD / CVE Program· CNA Linux

CVE-2021-47584: iocost: Fix divide-by-zero on donation from low hweight cgroup

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.25% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 3a1a4eb574178c21241a6200f4785572e661c472, a7c80674538f15f85d68138240aae440b8039519, edaa26334c117a584add6053f48d63a988d25a6e.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 3a1a4eb574178c21241a6200f4785572e661c472, a7c80674538f15f85d68138240aae440b8039519, edaa26334c117a584add6053f48d63a988d25a6e or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: iocost: Fix divide-by-zero on donation from low hweight cgroup The donation calculation logic assumes that the donor has non-zero after-donation hweight, so the lowest active hweight a donating cgroup can have is 2 so that it can donate 1 while keeping the other 1 for itself. Earlier, we only donated from cgroups with sizable surpluses so this condition was always true. However, with the precise donation algorithm implemented, f1de2439ec43 ("blk-iocost: revamp donation amount determination") made the donation amount calculation exact enabling even low hweight cgroups to donate. This means that in rare occasions, a cgroup with active hweight of 1 can enter donation calculation triggering the following warning and then a divide-by-zero oops. WARNING: CPU: 4 PID: 0 at block/blk-iocost.c:1928 transfer_surpluses.cold+0x0/0x53 [884/94867] ... RIP: 0010:transfer_surpluses.cold+0x0/0x53 Code: 92 ff 48 c7 c7 28 d1 ab b5 65 48 8b 34 25 00 ae 01 00 48 81 c6 90 06 00 00 e8 8b 3f fe ff 48 c7 c0 ea ff ff ff e9 95 ff 92 ff <0f> 0b 48 c7 c7 30 da ab b5 e8 71 3f fe ff 4c 89 e8 4d 85 ed 74 0 4 ... Call Trace: <IRQ> ioc_timer_fn+0x1043/0x1390 call_timer_fn+0xa1/0x2c0 __run_timers.part.0+0x1ec/0x2e0 run_timer_softirq+0x35/0x70 ... iocg: invalid donation weights in /a/b: active=1 donating=1 after=0 Fix it by excluding cgroups w/ active hweight < 2 from donating. Excluding these extreme low hweight donations shouldn't affect work conservation in any meaningful way.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 19, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 16th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.10 and later · before 5.10.88
  • linux linux kernel5.11 and later · before 5.15.11

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

    • 5.10affected
    • f1de2439ec43b74764f2a26e3a310b24407e3bde and later · before a7c80674538f15f85d68138240aae440b8039519affected · git
    • f1de2439ec43b74764f2a26e3a310b24407e3bde and later · before 3a1a4eb574178c21241a6200f4785572e661c472affected · git
    • f1de2439ec43b74764f2a26e3a310b24407e3bde and later · before edaa26334c117a584add6053f48d63a988d25a6eaffected · git
    • before 5.10not affected · semver
    • 5.10.88 and later · up to and including 5.10.*not affected · semver
    • 5.15.11 and later · up to and including 5.15.*not affected · semver
    • 5.16 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.15.15-15.15.15-1
openSUSE:Leap 15.5kernel-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1
openSUSE:Leap 15.5kernel-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
openSUSE:Leap 15.5kernel-rt_debugbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
openSUSE:Leap 15.5kernel-source-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1
openSUSE:Leap 15.5kernel-source-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
openSUSE:Leap 15.5kernel-syms-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1
openSUSE:Leap 15.5kernel-syms-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-64kbbefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-docsbefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-obs-buildbefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-sourcebefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-symsbefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_29before 1-150400.9.3.11-150400.9.3.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5-RT_Update_17before 1-150500.11.3.11-150500.11.3.1
SUSE:Linux Enterprise Micro 5.3kernel-defaultbefore 5.14.21-150400.24.128.15.14.21-150400.24.128.1
SUSE:Linux Enterprise Micro 5.3kernel-default-basebefore 5.14.21-150400.24.128.1.150400.24.62.15.14.21-150400.24.128.1.150400.24.62.1
SUSE:Linux Enterprise Micro 5.3kernel-rtbefore 5.14.21-150400.15.88.15.14.21-150400.15.88.1
SUSE:Linux Enterprise Micro 5.3kernel-source-rtbefore 5.14.21-150400.15.88.15.14.21-150400.15.88.1
SUSE:Linux Enterprise Micro 5.5kernel-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
SUSE:Linux Enterprise Micro 5.5kernel-source-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP5kernel-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP5kernel-source-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP5kernel-syms-azurebefore 5.14.21-150500.33.60.15.14.21-150500.33.60.1

+3

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-47582Jun 19, 2024 · USB: core: Make do_proc_control() and do_proc_bulk() killable
    22Monitor
  • ← EarlierCVE-2021-47583Jun 19, 2024 · media: mxl111sf: change mutex_init() location
    22Monitor
  • Later →CVE-2021-47585Jun 19, 2024 · btrfs: fix memory leak in __add_inode_ref()
    22Monitor

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 Linux3a1a4eb574178c21241a6200f4785572e661c472Vendor (CNA)
Linux Linuxa7c80674538f15f85d68138240aae440b8039519Vendor (CNA)
Linux Linuxedaa26334c117a584add6053f48d63a988d25a6eVendor (CNA)
debian:linux5.15.15-1 · Debian:12Package registry (OSV)
opensuse:kernel-azure5.14.21-150500.33.60.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-rt5.14.21-150500.13.61.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-rt_debug5.14.21-150500.13.61.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-source-azure5.14.21-150500.33.60.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-source-rt5.14.21-150500.13.61.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-syms-azure5.14.21-150500.33.60.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-syms-rt5.14.21-150500.13.61.1 · openSUSE:Leap 15.5Package registry (OSV)
suse:kernel-64kb5.14.21-150400.24.128.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-azure5.14.21-150500.33.60.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-default5.14.21-150400.24.128.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)
suse:kernel-default-base5.14.21-150400.24.128.1.150400.24.62.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_291-150400.9.3.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5-RT_Update_171-150500.11.3.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-rt5.14.21-150500.13.61.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-rt_debug5.14.21-150500.13.61.1 · SUSE:Real Time Module 15 SP5Package registry (OSV)
suse:kernel-source-azure5.14.21-150500.33.60.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-source-rt5.14.21-150500.13.61.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-syms-azure5.14.21-150500.33.60.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-syms-rt5.14.21-150500.13.61.1 · SUSE:Real Time Module 15 SP5Package 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.

No history yet (it accumulates with the daily EPSS job).

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

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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.

  • CVE-2024-2694549 days apartcrypto: iaa - Fix nr_cpus < nr_iaa case
    33Monitor
  • CVE-2021-476060 days apartnet: netlink: af_netlink: Prevent empty skb by adding a check on len.
    22Monitor
  • CVE-2024-3696911 days apartdrm/amd/display: Fix division by zero in setup_dsc_config
    22Monitor
  • CVE-2024-3947516 days apartfbdev: savage: Handle err return when savagefb_check_var failed
    22Monitor
  • CVE-2024-3690520 days aparttcp: defer shutdown(SEND_SHUTDOWN) for TCP_SYN_RECV sockets
    22Monitor
  • CVE-2021-4749528 days apartusbnet: sanity check for maxpacket
    22Monitor

Chain candidates

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

—

Bug bounty scope

No known public program.

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

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-369 · Divide By Zero

CVSS vector

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

nvd-primary

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.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

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

All records