Bug 2536153 (CVE-2026-93120)

Summary: CVE-2026-93120 kernel: usb: gadget: configfs: fix out-of-bounds read of qw_sign
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's USB gadget configfs component. This out-of-bounds read vulnerability occurs when the `os_desc_qw_sign_show()` function incorrectly handles string length during conversion. A local attacker could potentially exploit this to read sensitive information from memory, leading to information disclosure through the configfs attribute.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 16:40:56 UTC 
In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: configfs: fix out-of-bounds read of qw_sign

os_desc_qw_sign_show() passes OS_STRING_QW_SIGN_LEN as the input
length to utf16s_to_utf8s(), but that argument counts UTF-16 code
units while OS_STRING_QW_SIGN_LEN (14) is the byte size of qw_sign[].
The array holds only OS_STRING_QW_SIGN_LEN / 2 (7) code units, so the
conversion reads up to 7 units (14 bytes) past the end of qw_sign[]
into the following members of struct gadget_info when the stored
signature fills the array without a NUL terminator, exposing those
bytes through the configfs attribute.

The store path halves the count for its input bound but passes the
full byte count as the utf8s_to_utf16s() output limit; use the
destination code-unit count in both directions.
Comment 1 gkamathe 2026-09-19 17:17:01 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93120.mbox