# CVE-2026-80796: nfc: nci: add data_len bound checks to activation parameter extractors

CVE-2026-80796 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-80796, released September 5, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-80796
- Priority: Routine
- CVSS: 4.3 (Moderate)
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 4, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-80796

## Description

In the Linux kernel, the following vulnerability has been resolved:  nfc: nci: add data_len bound checks to activation parameter extractors  nci_extract_activation_params_iso_dep() and nci_extract_activation_params_nfc_dep() read an inner length byte from the NCI RF_INTF_ACTIVATED_NTF payload and use it to memcpy() into fixed kernel buffers, but neither function receives the caller-validated activation_params_len.  A crafted NCI notification with activation_params_len=1 and an inner length byte of up to 20 (NFC-A) or 50 (NFC-B) causes memcpy() to read that many bytes past the one valid byte in the activation params region -- a slab out-of-bounds read of kernel memory adjacent to the NCI skb.  The sibling nci_extract_rf_params_*() family was given equivalent protection by commit 571dcbeb8e63 ("net: nfc: nci: Fix parameter validation for packet data"), but the two activation parameter extractors were not updated at that time.  Add a data_len parameter to both functions, guard against an empty region before consuming the inner length byte, decrement the remaining count after consuming it, and clamp the copy length to what is actually available.  Update both call sites to pass ntf.activation_params_len, which is already validated against the skb at ntf.c:801.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.187-1 | [DEBIAN-CVE-2026-80796](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80796.md) | Sep 5, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-80796](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80796.md) | Sep 5, 2026 |
| Linux | linux Debian 14 | 7.1.12-1 | [DEBIAN-CVE-2026-80796](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80796.md) | Sep 5, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-80796](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80796.md) | Sep 5, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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