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CVE-2021-47577· NVD / CVE Program· CNA Linux

io-wq: check for wq exit after adding new worker task_work

In the Linux kernel, the following vulnerability has been resolved: io-wq: check for wq exit after adding new worker task_work We check IO_WQ_BIT_EXIT before attempting to create a new worker, and wq exit cancels pending work if we have any. But it's possible to have a race between the two, where creation checks exit finding it not set, but we're in the process of exiting. The exit side will cancel pending creation task_work, but there's a gap where we add task_work after we've canceled existing creations at exit time. Fix this by checking the EXIT bit post adding the creation task_work. If it's set, run the same cancelation that exit does.

MediumCVSS 4.7 · v3.1—No exploit Fix available
Published
Jun 19, 2024
Updated
Aug 5, 2026
EPSS
0.2% · 4th percentile
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Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.7 / 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.

CNA vs NVD score

NVD
4.7
CNA · Linux
7.8
3.1 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

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 kernelbefore 5.15.11
  • linux linux kernel5.16

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

    • 5.13affected
    • 685fe7feedb96771683437107ba72131410e2350 and later · before 4b4e5bbf9386d4ec21d91c0cb0fd60b9bba778ecaffected · git
    • 685fe7feedb96771683437107ba72131410e2350 and later · before 71a85387546e50b1a37b0fa45dadcae3bfb35cf6affected · git
    • before 5.13not 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 15.5dtb-aarch64before 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-debugbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-kvmsmallbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
openSUSE:Leap 15.5kernel-obs-qabefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_17before 1-150500.11.3.11-150500.11.3.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_17before 1-150500.11.3.11-150500.11.3.1
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 Live Patching 15 SP5kernel-livepatch-SLE15-SP5-RT_Update_17before 1-150500.11.3.11-150500.11.3.1
SUSE:Linux Enterprise Micro 5.5kernel-defaultbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Micro 5.5kernel-defaultbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Micro 5.5kernel-default-basebefore 5.14.21-150500.55.73.1.150500.6.33.85.14.21-150500.55.73.1.150500.6.33.8
SUSE:Linux Enterprise Micro 5.5kernel-default-basebefore 5.14.21-150500.55.73.1.150500.6.33.85.14.21-150500.55.73.1.150500.6.33.8
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-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 Micro 5.5kernel-source-rtbefore 5.14.21-150500.13.61.15.14.21-150500.13.61.1
SUSE:Linux Enterprise Module for Basesystem 15 SP5kernel-64kbbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP5kernel-64kbbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP5kernel-sourcebefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP5kernel-sourcebefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP5kernel-zfcpdumpbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP5kernel-zfcpdumpbefore 5.14.21-150500.55.73.15.14.21-150500.55.73.1
SUSE:Linux Enterprise Module for Development Tools 15 SP5kernel-docsbefore 5.14.21-150500.55.73.25.14.21-150500.55.73.2

+15

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    85Now
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    83Now
  • CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV
    77This week
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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 Linux4b4e5bbf9386d4ec21d91c0cb0fd60b9bba778ecVendor (CNA)
Linux Linux71a85387546e50b1a37b0fa45dadcae3bfb35cf6Vendor (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-source-azure5.14.21-150500.33.60.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-syms-azure5.14.21-150500.33.60.1 · openSUSE:Leap 15.5Package registry (OSV)
suse:kernel-azure5.14.21-150500.33.60.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package 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.

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.

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.

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.

—

Bug bounty scope

No known public program.

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

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.
  • Special conditions such as timing or configuration are required.

If successful

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

CVSS vector

CVSS:3.1/AV:L/AC:H/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.

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

  1. Fix✗ → ✓

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References

All records