# CVE-2026-31696: rxrpc: Fix missing validation of ticket length in non-XDR key preparsing

CVE-2026-31696 is fixed in 36 products on 1 platform, first by DEBIAN-CVE-2026-31696, released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-31696
- Priority: High
- CVSS: 7.8 (Moderate)
- EPSS: 0.0014
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 1, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-31696

## Description

In the Linux kernel, the following vulnerability has been resolved:  rxrpc: Fix missing validation of ticket length in non-XDR key preparsing  In rxrpc_preparse(), there are two paths for parsing key payloads: the XDR path (for large payloads) and the non-XDR path (for payloads <= 28 bytes). While the XDR path (rxrpc_preparse_xdr_rxkad()) correctly validates the ticket length against AFSTOKEN_RK_TIX_MAX, the non-XDR path fails to do so.  This allows an unprivileged user to provide a very large ticket length. When this key is later read via rxrpc_read(), the total token size (toksize) calculation results in a value that exceeds AFSTOKEN_LENGTH_MAX, triggering a WARN_ON().  [ 2001.302904] WARNING: CPU: 2 PID: 2108 at net/rxrpc/key.c:778 rxrpc_read+0x109/0x5c0 [rxrpc]  Fix this by adding a check in the non-XDR parsing path of rxrpc_preparse() to ensure the ticket length does not exceed AFSTOKEN_RK_TIX_MAX, bringing it into parity with the XDR parsing logic.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | kernel-uek ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-devel ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-devel ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-deprecated ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-deprecated ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-desktop ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-desktop ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-extra ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-extra ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-extra-netfilter ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-extra-netfilter ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-usb ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-usb ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-wireless ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-debug-modules-wireless ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-devel ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-devel ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-doc ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-doc ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-deprecated ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-deprecated ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-desktop ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-desktop ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-extra ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-extra ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-extra-netfilter ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-extra-netfilter ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-usb ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-usb ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-wireless ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-modules-wireless ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-tools ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek-tools ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-devel ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-devel ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-deprecated ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-deprecated ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-desktop ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-desktop ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-extra ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-extra ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-extra-netfilter ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-extra-netfilter ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-usb ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-usb ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-wireless ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | kernel-uek64k-modules-wireless ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 |
| Linux | linux Debian 12.15 (bookworm) | 6.1.176-1 | [DEBIAN-CVE-2026-31696](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31696.md) | May 15, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.85-1 | [DEBIAN-CVE-2026-31696](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31696.md) | May 15, 2026 |
| Linux | linux Debian 14 | 7.0.3-1 | [DEBIAN-CVE-2026-31696](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31696.md) | May 15, 2026 |

---

Data as of 2026-11-09T07:25:28Z 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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