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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98537: workqueue: Fix NULL current_pwq deref in flush dependency check

Noroxi assessment

Priority: Monitor (action score 0/100)

  • 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: 0.22% (FIRST EPSS).
  • Fixed version: Linux Linux 0c6b9b1e295aeff1132ac7aa738148cc65f06485, 1dccf5dc2f8fe688270b261ca4216e03c6a1e674, 513121e69388604619ea8c0ee07e86a3d1b5b5dc; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0c6b9b1e295aeff1132ac7aa738148cc65f06485, 1dccf5dc2f8fe688270b261ca4216e03c6a1e674, 513121e69388604619ea8c0ee07e86a3d1b5b5dc; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1 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: workqueue: Fix NULL current_pwq deref in flush dependency check check_flush_dependency() uses current_wq_worker() to determine whether the caller is a workqueue worker and then dereferences worker->current_pwq to test whether the current workqueue is WQ_MEM_RECLAIM. current_wq_worker() only means that %current has PF_WQ_WORKER set. A kworker can reach check_flush_dependency() while it is not executing a work item. One such path is worker_thread() acting as the pool manager, where create_worker() does GFP_KERNEL allocation and the allocation path invokes the OOM notifier. In that state worker->current_pwq is NULL because current_pwq is set only by process_one_work() and cleared again after the work function returns. [ 416.760634][ T375] Call trace: [ 416.760638][ T375] check_flush_dependency+0x80/0x120 (P) [ 416.760648][ T375] __flush_work+0x98/0x224 [ 416.760657][ T375] flush_work+0x30/0x44 [ 416.760665][ T375] ... [ 416.760710][ T375] blocking_notifier_call_chain+0x58/0xa0 [ 416.760719][ T375] out_of_memory+0xb4/0x458 [ 416.760730][ T375] __alloc_pages_may_oom+0x11c/0x1a8 [ 416.760739][ T375] __alloc_pages_slowpath+0x314/0x46c [ 416.760746][ T375] __alloc_frozen_pages_noprof+0x110/0x1a4 [ 416.760753][ T375] new_slab+0x12c/0x484 [ 416.760759][ T375] ___slab_alloc+0x7a8/0xc7c [ 416.760765][ T375] __slab_alloc+0x74/0xd8 [ 416.760772][ T375] __kmalloc_cache_node_noprof+0x2ac/0x304 [ 416.760779][ T375] alloc_worker+0x28/0x60 [ 416.760785][ T375] create_worker+0x4c/0x20c [ 416.760790][ T375] worker_thread+0xe8/0x2b8 [ 416.760796][ T375] kthread+0x1a8/0x200 [ 416.760805][ T375] ret_from_fork+0x10/0x20 Guard the WQ_MEM_RECLAIM-worker warning with worker->current_pwq. If the kworker is not currently executing a work item, there is no current workqueue to diagnose with that warning. The PF_MEMALLOC warning is left unchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target is still reported.

—No exploit Fix available
Published
Oct 18, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 12th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

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

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Noroxi analysis

What does it mean in your environment?

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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.

—

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

    • 4.5affected
    • fca839c00a12d682cb59b3b620d109a1d850b262 and later · before 8ffececcb88262389b4f91fed0fe4884b68204bcaffected · git
    • fca839c00a12d682cb59b3b620d109a1d850b262 and later · before 9bb739a5c5a570c28a62afb98e9326e2a49743c1affected · git
    • fca839c00a12d682cb59b3b620d109a1d850b262 and later · before cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3affected · git
    • fca839c00a12d682cb59b3b620d109a1d850b262 and later · before 513121e69388604619ea8c0ee07e86a3d1b5b5dcaffected · git
    • fca839c00a12d682cb59b3b620d109a1d850b262 and later · before 0c6b9b1e295aeff1132ac7aa738148cc65f06485affected · git
    • fca839c00a12d682cb59b3b620d109a1d850b262 and later · before 1dccf5dc2f8fe688270b261ca4216e03c6a1e674affected · git
    • fca839c00a12d682cb59b3b620d109a1d850b262 and later · before f97e6d0572d1b39998e053732332bc3cfdd0b9aaaffected · git
    • fca839c00a12d682cb59b3b620d109a1d850b262 and later · before db6365ced4d5855e321f772b240c0e473bcfcdd5affected · git
    • before 4.5not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.113-1~deb12u16.12.113-1~deb12u1
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.9-17.2.9-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-98535Oct 18, 2026 · fsl/fman: Fix clk reference leak in read_dts_node()
    0Monitor
  • ← EarlierCVE-2026-98536Oct 18, 2026 · writeback: report a Tasks-RCU quiescent state per cgwb drain pass
    0Monitor
  • Later →CVE-2026-98538Oct 18, 2026 · writeback: bound cleanup_offline_cgwb() rescans by rotating scanned inodes
    0Monitor

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 Linux0c6b9b1e295aeff1132ac7aa738148cc65f06485Vendor (CNA)
Linux Linux1dccf5dc2f8fe688270b261ca4216e03c6a1e674Vendor (CNA)
Linux Linux513121e69388604619ea8c0ee07e86a3d1b5b5dcVendor (CNA)
Linux Linux8ffececcb88262389b4f91fed0fe4884b68204bcVendor (CNA)
Linux Linux9bb739a5c5a570c28a62afb98e9326e2a49743c1Vendor (CNA)
Linux Linuxcc190a6a1d20b87e6a9435202fc2a3bd84c79fb3Vendor (CNA)
Linux Linuxdb6365ced4d5855e321f772b240c0e473bcfcdd5Vendor (CNA)
Linux Linuxf97e6d0572d1b39998e053732332bc3cfdd0b9aaVendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.159.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.113-1~deb12u1 · 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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 2, 2026+15 d
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

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).

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

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.

Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

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References

Show all references (7 more)

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

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