# CVE-2026-72138: xen/gntdev: fix error handling in ioctl

Status: published. Published: 2026-08-15. Updated: 2026-11-06.

In the Linux kernel, the following vulnerability has been resolved:

xen/gntdev: fix error handling in ioctl

When gntdev_ioctl_map_grant_ref() fails to copy the operation result
back to userspace after successfully adding the mapping to the list,
the error path returns -EFAULT without releasing the reference
acquired by gntdev_alloc_map(). The mapping remains in priv->maps
with a refcount of 1, causing a memory leak and a dangling list
entry.

Additionally, gntdev_add_map() may modify map->index to avoid overlap
with existing mappings. Therefore, the index returned to userspace
must be obtained after gntdev_add_map() completes.

Fix this by holding the mutex across gntdev_add_map(), retrieving
the correct index, and copy_to_user(). If copy_to_user() fails,
remove the mapping from the list and release the reference while
still holding the lock.


Fix these issues by properly handling all error cases.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 68b025c813c2eb41ff25628e3d4952d5185eb1a4; < 52dc40ef0cfee6ae89b7524967e73f0ba37906d7 (affected, git); ≥ 68b025c813c2eb41ff25628e3d4952d5185eb1a4; < 1dd9cb98fe228e017fff9efb33862ff38c741b65 (affected, git); ≥ 68b025c813c2eb41ff25628e3d4952d5185eb1a4; < 6df926130aee6cab9b5d2e5b7862e49ccac348dc (affected, git); ≥ 68b025c813c2eb41ff25628e3d4952d5185eb1a4; < 311011f8cc206c5af2877b03e3f627ee1b8fe024 (affected, git); ≥ 68b025c813c2eb41ff25628e3d4952d5185eb1a4; < 18a693733f7ad004e1ab0466693121ca70cd95dd (affected, git); ≥ 68b025c813c2eb41ff25628e3d4952d5185eb1a4; < 16d3ccdabb8dee9be2cdcd6d3f9a125572ec0454 (affected, git); ≥ 68b025c813c2eb41ff25628e3d4952d5185eb1a4; < 6883269a323609f68f6faa903f8f8ff3d191cec8 (affected, git); ≥ 68b025c813c2eb41ff25628e3d4952d5185eb1a4; < 45ca1afe2fd14c04e37227e79d3f8455831d8408 (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.39 (affected); ≥ 0; < 2.6.39 (unaffected, semver); ≥ 5.10.261; ≤ 5.10.* (unaffected, semver); ≥ 5.15.212; ≤ 5.15.* (unaffected, semver); ≥ 6.1.178; ≤ 6.1.* (unaffected, semver); ≥ 6.6.145; ≤ 6.6.* (unaffected, semver); ≥ 6.12.97; ≤ 6.12.* (unaffected, semver); ≥ 6.18.40; ≤ 6.18.* (unaffected, semver); ≥ 7.1.5; ≤ 7.1.* (unaffected, semver); ≥ 7.2; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.22% as of 2026-11-06; percentile 12.14%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/52dc40ef0cfee6ae89b7524967e73f0ba37906d7 (CNA: Linux)

- https://git.kernel.org/stable/c/1dd9cb98fe228e017fff9efb33862ff38c741b65 (CNA: Linux)

- https://git.kernel.org/stable/c/6df926130aee6cab9b5d2e5b7862e49ccac348dc (CNA: Linux)

- https://git.kernel.org/stable/c/311011f8cc206c5af2877b03e3f627ee1b8fe024 (CNA: Linux)

- https://git.kernel.org/stable/c/18a693733f7ad004e1ab0466693121ca70cd95dd (CNA: Linux)

- https://git.kernel.org/stable/c/16d3ccdabb8dee9be2cdcd6d3f9a125572ec0454 (CNA: Linux)

- https://git.kernel.org/stable/c/6883269a323609f68f6faa903f8f8ff3d191cec8 (CNA: Linux)

- https://git.kernel.org/stable/c/45ca1afe2fd14c04e37227e79d3f8455831d8408 (CNA: Linux)

- https://git.kernel.org/stable/c/16d3ccdabb8dee9be2cdcd6d3f9a125572ec0454 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/18a693733f7ad004e1ab0466693121ca70cd95dd (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/1dd9cb98fe228e017fff9efb33862ff38c741b65 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/311011f8cc206c5af2877b03e3f627ee1b8fe024 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/45ca1afe2fd14c04e37227e79d3f8455831d8408 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/52dc40ef0cfee6ae89b7524967e73f0ba37906d7 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/6883269a323609f68f6faa903f8f8ff3d191cec8 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/6df926130aee6cab9b5d2e5b7862e49ccac348dc (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-72138; retrieved 2026-11-06; source updated 2026-11-06

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72138; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-72138; retrieved 2026-11-06; source updated Not reported

Revision: 55555b607b608010f3fd153f48f7631a726dde7a59f9f8e75174d56c210de693

Canonical: https://y2.dev/cve/CVE-2026-72138

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