NVD / CVE Program· CNA Linux

CVE-2026-64073: irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT

Noroxi assessment

Priority: Monitor (action score 31/100)

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: 0.13% (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 18c0456ea2615b1a743a6db739c74411c3b42bc6, 2dc79362302922cb18f35e262712b5e58de65442, 684a78183c54c23e70d1cba320f7fc184604210b.

Low priority for now. Upgrade to Linux Linux 18c0456ea2615b1a743a6db739c74411c3b42bc6, 2dc79362302922cb18f35e262712b5e58de65442, 684a78183c54c23e70d1cba320f7fc184604210b 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: irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT On PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via run_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0. After irq_work_single() clears BUSY via atomic_cmpxchg(), it still dereferences @work for irq_work_is_hard() and rcuwait_wake_up(). An irq_work_sync() caller on another CPU that enters after BUSY is cleared can observe BUSY==0 immediately, return, and free the work before those accesses complete — causing a use-after-free. Fix this by wrapping run_irq_workd() in guard(rcu)() so that the entire irq_work_single() execution is within an RCU read-side critical section. Then add synchronize_rcu() in irq_work_sync() after rcuwait_wait_event() to ensure the caller waits for the RCU grace period before returning, preventing premature frees.

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

Published: Jul 19, 2026
Updated: Oct 19, 2026
EPSS: 0.1% · 2th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Linux: 7.8; NVD has not scored this yet; the score shown is the CNA’s.

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

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.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

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

linux linux kernel5.16 and later · before 6.1.175
linux linux kernel6.2 and later · before 6.6.142
linux linux kernel6.7 and later · before 6.12.92
linux linux kernel6.13 and later · before 6.18.34
linux linux kernel6.19 and later · before 7.0.11
linux linux kernel7.1

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
- 5.16affected
- 810979682ccc98dbd83f341c18a2e556c30a7164 and later · before 2dc79362302922cb18f35e262712b5e58de65442affected · git
- 810979682ccc98dbd83f341c18a2e556c30a7164 and later · before eef4f71b46a9929ac33e968538c9dd5d96a02460affected · git
- 810979682ccc98dbd83f341c18a2e556c30a7164 and later · before 684a78183c54c23e70d1cba320f7fc184604210baffected · git
- 810979682ccc98dbd83f341c18a2e556c30a7164 and later · before 18c0456ea2615b1a743a6db739c74411c3b42bc6affected · git
- 810979682ccc98dbd83f341c18a2e556c30a7164 and later · before 81b582784518196eff1050212a046bc29d3a05ddaffected · git
- 810979682ccc98dbd83f341c18a2e556c30a7164 and later · before 91840be8f710370607f949a627e070896faeddb8affected · git
- before 5.16not affected · semver
- 6.1.175 and later · up to and including 6.1.*not affected · semver
- 6.6.142 and later · up to and including 6.6.*not affected · semver

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.176-1	6.1.176-1
Debian:13	linux	before 6.12.94-1	6.12.94-1
Debian:14	linux	before 7.0.12-1	7.0.12-1

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-2026-64067Jul 19, 2026 · netfs: Fix missing barriers when accessing stream->subrequests locklessly
39Monitor
← EarlierCVE-2026-64068Jul 19, 2026 · netfs: Fix missing locking around retry adding new subreqs
39Monitor
Later →CVE-2026-64076Jul 19, 2026 · netfilter: bridge: eb_tables: close module init race
31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	18c0456ea2615b1a743a6db739c74411c3b42bc6	Vendor (CNA)
Linux Linux	2dc79362302922cb18f35e262712b5e58de65442	Vendor (CNA)
Linux Linux	684a78183c54c23e70d1cba320f7fc184604210b	Vendor (CNA)
Linux Linux	81b582784518196eff1050212a046bc29d3a05dd	Vendor (CNA)
Linux Linux	91840be8f710370607f949a627e070896faeddb8	Vendor (CNA)
Linux Linux	eef4f71b46a9929ac33e968538c9dd5d96a02460	Vendor (CNA)
debian:linux	6.1.176-1 · Debian:12	Package 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

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: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

SSVC exploitation— → noneOct 16, 2026, 5:07 PM UTC
Fix✗ → ✓Sep 28, 2026, 10:11 PM UTC

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

References

git.kernel.org/stable/c/18c0456ea2615b1a743a6db739c74411c3b42bc6

Show all references (5 more)

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

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