Bug 2554900 (CVE-2026-98482)
| Summary: | CVE-2026-98482 kernel: nfc: llcp: drop truncated I/RR/RNR PDUs in nfc_llcp_recv_hdlc() | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | 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) subsystem. The Logical Link Control Protocol (LLCP) implementation does not verify the length of incoming network packets before reading sequence information. An attacker within NFC radio range could exploit this by transmitting truncated packets, causing the kernel to read uninitialized memory. This flaw may lead to unexpected connection behavior or a Denial of Service (DoS).
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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: | |||
In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: drop truncated I/RR/RNR PDUs in nfc_llcp_recv_hdlc() nfc_llcp_recv_hdlc() reads the sequence byte skb->data[2], via nfc_llcp_ns()/nfc_llcp_nr(), before any length check. The receive path only guarantees the two-byte LLCP header -- __nfc_llcp_recv() checks it with pskb_may_pull() and nfc_llcp_recv_agf() admits two-byte inner PDUs -- so a two-byte I, RR or RNR PDU reads one byte of uninitialised skb tailroom. The byte becomes N(R)/N(S); a peer can already set those with a well-formed PDU, so this is acting on uninitialised memory, not new peer control. Guard the read with pskb_may_pull(), as commit 95674f506c63 ("nfc: llcp: reject PDUs shorter than the LLCP header") did for the two-byte header, so the sequence byte is present and linear before it is read. RR and RNR PDUs are LLCP_HEADER_SIZE + LLCP_SEQUENCE_SIZE bytes and an I PDU is longer, so no valid frame is rejected; a truncated PDU is malformed, so return without a DM reply.