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.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
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Thu, 17 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | nfc: llcp: avoid userspace overflow on invalid optlen | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-17T16:07:35.322Z
Reserved: 2026-09-11T19:38:34.794Z
Link: CVE-2026-90226
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:17:18.270
Modified: 2026-09-17T17:17:18.270
Link: CVE-2026-90226
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.