VulnerabilityPublished 4 Sep 2026Updated 30 Sep 2026

CVE-2026-80821: Linux kernel · nvmet: pci-epf: put CQ ref on create_cq mapping failure

Affects Linux kernelSource GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-xgj8-pp4r-hmxg

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-34.34 22 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1013.13 14 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1014.14 14 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1013.13 8 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1013.13 12 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1007.8 5 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix has been implemented in the Linux kernel to release the CQ reference on mapping failure paths in nvmet_pci_epf_create_cq(). Users should update to a kernel version that includes this patch. Since this is a kernel-level fix, no additional mitigation is required beyond applying the official patch when available.

Description

In the Linux kernel, the following vulnerability has been resolved: nvmet: pci-epf: put CQ ref on create_cq mapping failure nvmet_pci_epf_create_cq() calls nvmet_cq_create(), which takes a reference on the controller and installs the completion queue. If the subsequent PCI address-space mapping fails or returns a too-small partial mapping, the function jumps to err_internal / err_unmap_queue without calling nvmet_cq_put(). The matching put in nvmet_pci_epf_delete_cq() is gated on NVMET_PCI_EPF_Q_LIVE, which is only set after the mapping succeeds, so teardown never releases these references. A remote PCI host that drives Create IO CQ commands with a failing PRP1/pci_addr therefore leaks the CQ and a controller reference on each attempt. Drop the CQ reference on the mapping-failure paths. The err_internal and err_unmap_queue labels are only reachable after nvmet_cq_create() has succeeded, so this pairs the create/put correctly.

Impact

The vulnerability causes resource leaks in the Linux kernel's nvmet PCI endpoint driver when handling certain IO completion queue creation failures. A remote PCI host can trigger repeated leaks of completion queue and controller references by sending malformed Create IO CQ commands. This could lead to resource exhaustion on the affected system over time. There is no indication of direct code execution or privilege escalation from this issue.

Summary

The Linux kernel's nvmet_pci_epf_create_cq() function calls nvmet_cq_create(), which acquires a reference on the controller and installs a completion queue. If PCI address-space mapping fails or returns an insufficient partial mapping, the error handling paths previously did not call nvmet_cq_put() to release the acquired reference. Since the corresponding release in nvmet_pci_epf_delete_cq() depends on a flag set only after successful mapping, references were leaked on failure. This vulnerability allows a remote PCI host issuing Create IO CQ commands with failing PRP1/pci_addr to leak completion queue and controller references repeatedly. The patch adds calls to release the CQ reference on these failure paths, properly pairing create and put operations.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 7 Sep 2026, 12:08 UTC

Technical details

References

Community reviews

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