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NVD / CVE Program· CNA Linux

CVE-2026-80920: io_uring: defer eventfd signaling when queued from a wakeup handler

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: 0.16% (FIRST EPSS).
  • Fixed version: Linux Linux 40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a, 9d984451baf768ecd9e1fdad4637b729fcb2c9d5, b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a, 9d984451baf768ecd9e1fdad4637b729fcb2c9d5, b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes 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: io_uring: defer eventfd signaling when queued from a wakeup handler io_req_local_work_add() signals the CQ ring eventfd inline when it is the one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that add is frequently done from a waitqueue wakeup handler, where an arbitrary waitqueue lock is held. eventfd_signal_mask() only refuses to recurse when current->in_eventfd is set, but that bit is set by eventfd_signal_mask() itself. If the wake chain starts somewhere else, signal goes out inline and can feed back into epoll. Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three waitqueue callbacks, and use it to force io_eventfd_signal() down the existing call_rcu_hurry() deferral instead of signaling inline.

—No exploit Fix available
Published
Sep 9, 2026
Updated
Oct 21, 2026
EPSS
0.1% · 5th 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 · 0.1%

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  • 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.

—

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

    • 6.1affected
    • 21a091b970cdbcf3e8ff829234b51be6f9192766 and later · before d0c240f25e654442a72af5ca021a02165ccce638affected · git
    • 21a091b970cdbcf3e8ff829234b51be6f9192766 and later · before 9d984451baf768ecd9e1fdad4637b729fcb2c9d5affected · git
    • 21a091b970cdbcf3e8ff829234b51be6f9192766 and later · before e22f4494cc9487d326e5e3067f33dea7c1e442b2affected · git
    • 21a091b970cdbcf3e8ff829234b51be6f9192766 and later · before b6bb334b0e9348887e3e55e1f494b0c3b8fbf59faffected · git
    • 21a091b970cdbcf3e8ff829234b51be6f9192766 and later · before 40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5aaffected · git
    • 21a091b970cdbcf3e8ff829234b51be6f9192766 and later · before cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6eaffected · git
    • before 6.1not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver
    • 6.12.114 and later · up to and including 6.12.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:14linuxbefore 7.1.12-17.1.12-1

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-2026-80917Sep 9, 2026 · PCI: host-generic: Fix NULL pointer dereference on 32-bit CAM systems
    0Monitor
  • ← EarlierCVE-2026-80918Sep 9, 2026 · HID: core: fix number/pointer type confusion on long items
    0Monitor
  • Later →CVE-2026-80921Sep 9, 2026 · KVM: s390: vsie: zero stale crypto bits
    35Monitor

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 Linux40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5aVendor (CNA)
Linux Linux9d984451baf768ecd9e1fdad4637b729fcb2c9d5Vendor (CNA)
Linux Linuxb6bb334b0e9348887e3e55e1f494b0c3b8fbf59fVendor (CNA)
Linux Linuxcd305ee3633a45fcf5f3a5d83f99f3cb77d87b6eVendor (CNA)
Linux Linuxd0c240f25e654442a72af5ca021a02165ccce638Vendor (CNA)
Linux Linuxe22f4494cc9487d326e5e3067f33dea7c1e442b2Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux7.1.12-1 · Debian:14Package 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

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

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. Fix✗ → ✓

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References

Show all references (5 more)

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

All records