# CVE-2026-74647: misc: fastrpc: Remove buffer from list prior to unmap operation

CVE-2026-74647 is fixed in 12 products on 1 platform, first by DEBIAN-CVE-2026-74647, released August 27, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-74647
- Priority: High
- CVSS: 7.8 (Moderate)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 22, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74647

## Description

In the Linux kernel, the following vulnerability has been resolved:  misc: fastrpc: Remove buffer from list prior to unmap operation  fastrpc_req_munmap_impl() is called to unmap any buffer. The buffer is getting removed from the list after it is unmapped from DSP. This can create potential race conditions if multiple threads invoke unmap concurrently, where one thread may remove the entry from the list while another thread's unmap operation is still ongoing.  Fix this by removing the buffer entry from the list before calling the unmap operation. If the unmap fails, the entry is re-added to the list so that userspace can retry the unmap, or alternatively, the buffer will be cleaned up during device release when the DSP process is torn down and all DSP-side mappings are freed along with remaining buffers in the list.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-default sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.90.1.150700.17.51.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-livepatch-SLE15-SP7_Update_24 sles 15.7 | 1-150700.15.3.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-source sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.90.1 | [SUSE-SU-2026:5091-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5091-1.md) | Nov 7, 2026 |
| Linux | linux Debian 12.15 (bookworm) | 6.1.187-1 | [DEBIAN-CVE-2026-74647](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74647.md) | Aug 27, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.105-1 | [DEBIAN-CVE-2026-74647](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74647.md) | Aug 27, 2026 |
| Linux | linux Debian 14 | 7.1.9-1 | [DEBIAN-CVE-2026-74647](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74647.md) | Aug 27, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.107-1~deb12u1 | [DEBIAN-CVE-2026-74647](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74647.md) | Aug 27, 2026 |

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Data as of 2026-11-08T13:06:02Z 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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