CVE-2026-90044

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Fix Use-After-Free in AIO error path In ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io() fails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is freed. However, for AIO operations, the kiocb cancel function was already armed and kiocb->private was set to `p`. If a concurrent cancel operation (such as sys_io_cancel()) executes after ffs_epfile_io() fails but before the function frees `p`, a Use-After-Free can occur when the cancellation handler accesses the freed pointer. To securely fix this race condition, we must properly un-arm the cancellation. Invoking `kiocb->ki_complete()` does exactly this by acquiring `ctx->ctx_lock` and safely removing the kiocb from the active sequence. In doing so, it ensures that a parallel io_cancel can no longer discover the kiocb, effectively closing the race window. We then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been consumed and it should avoid attempting to complete the request again or triggering subsequent completion handlers.

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce
https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc
https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7

Configurations

No configuration.

History

16 Sep 2026, 15:18

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.8

Information

Published : 2026-09-16 11:17

Updated : 2026-09-16 15:18

NVD link : CVE-2026-90044

Mitre link : CVE-2026-90044

CVE.ORG link : CVE-2026-90044

JSON object : View

Products Affected

No product.

CWE

No CWE.

{"id": "CVE-2026-90044", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.8}]}, "affected": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "affectedData": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "de2080d41b5d584205e408d72021f0f335a046fc", "lessThan": "153b5ecd29ed055562400bc17c91df3fd869b0ce", "versionType": "git"}, {"status": "affected", "version": "de2080d41b5d584205e408d72021f0f335a046fc", "lessThan": "4a2fb2d12b87b43724230abb52a1440617c7b6cc", "versionType": "git"}, {"status": "affected", "version": "de2080d41b5d584205e408d72021f0f335a046fc", "lessThan": "e78dcb1f7ec271449c54984dc90c62a5ba272de7", "versionType": "git"}], "programFiles": ["drivers/usb/gadget/function/f_fs.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4.0"}, {"status": "unaffected", "version": "0", "lessThan": "4.0", "versionType": "semver"}, {"status": "unaffected", "version": "6.18.51", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.2.5", "versionType": "semver", "lessThanOrEqual": "7.2.*"}, {"status": "unaffected", "version": "7.3-rc1", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["drivers/usb/gadget/function/f_fs.c"], "defaultStatus": "affected"}]}], "published": "2026-09-16T11:17:17.660", "references": [{"url": "https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Received", "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix Use-After-Free in AIO error path\n\nIn ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io()\nfails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is\nfreed. However, for AIO operations, the kiocb cancel function was already\narmed and kiocb->private was set to `p`.\n\nIf a concurrent cancel operation (such as sys_io_cancel()) executes after\nffs_epfile_io() fails but before the function frees `p`, a Use-After-Free\ncan occur when the cancellation handler accesses the freed pointer.\n\nTo securely fix this race condition, we must properly un-arm the\ncancellation. Invoking `kiocb->ki_complete()` does exactly this by\nacquiring `ctx->ctx_lock` and safely removing the kiocb from the active\nsequence. In doing so, it ensures that a parallel io_cancel can no longer\ndiscover the kiocb, effectively closing the race window.\n\nWe then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been\nconsumed and it should avoid attempting to complete the request again or\ntriggering subsequent completion handlers."}], "lastModified": "2026-09-16T15:18:27.100", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}