Bug 2536569 (CVE-2026-90226)

Summary: CVE-2026-90226 kernel: nfc: llcp: avoid userspace overflow on invalid optlen
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's Near Field Communication (NFC) Logical Link Control Protocol (LLCP) subsystem. A local user could trigger a buffer overflow in the `nfc_llcp_getsockopt()` function by supplying an invalid option length. This improper handling allows the kernel to write past the user-supplied buffer, potentially leading to information disclosure or a denial of service (DoS).
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 18:27:30 UTC 
In the Linux kernel, the following vulnerability has been resolved:

nfc: llcp: avoid userspace overflow on invalid optlen

nfc_llcp_getsockopt() casts optval to (u32 __user *) for put_user(), so
the kernel always stores 4 bytes regardless of the caller-supplied
optlen. The existing min_t(u32, len, sizeof(u32)) only clamps the length
reported back to userspace; it does not constrain the store. A call with
optlen < 4 therefore writes past the user buffer, violating the
getsockopt(2) contract for all five supported optnames.

Reject any call with optlen < sizeof(u32) up front. 'len' is int, so a
plain size comparison would promote a negative optlen to size_t and slip
past the check; an explicit 'len < 0' test is added first to catch
negative values before the size compare.
Comment 1 Mauro Matteo Cascella 2026-09-24 14:10:39 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90226.mbox