# CVE-2026-98524: rds: ib: Clear the sg list when mapping an MR fails

CVE-2026-98524 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-98524, released October 19, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-98524
- Priority: High
- CVSS: 7.8 (Important)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 18, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98524

## Description

In the Linux kernel, the following vulnerability has been resolved:  rds: ib: Clear the sg list when mapping an MR fails  rds_ib_map_frmr() stores the caller's scatterlist in the MR before DMA mapping and registration can fail. On failure, __rds_rdma_map() unpins the pages and frees the scatterlist, but rds_ib_free_frmr() can still return the MR to the pool with the stale pointer set.  This leaves the pool with a dangling scatterlist and can lead to local privilege escalation. KASAN detects the resulting use-after-free when the MR is later torn down:  BUG: KASAN: slab-use-after-free in __rds_ib_teardown_mr Read of size 8  Call Trace:  __rds_ib_teardown_mr  rds_ib_unreg_frmr  rds_ib_flush_mr_pool  rds_ib_flush_mrs  rds_free_mr  rds_setsockopt  Store the scatterlist in the MR only after DMA mapping succeeds. If DMA mapping fails, return directly while the MR fields remain clear; the caller keeps ownership of the scatterlist and its pinned pages. If a later registration step fails, unmap the scatterlist and clear the MR fields before returning.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.190-1 | [DEBIAN-CVE-2026-98524](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98524.md) | Oct 19, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.113-1 | [DEBIAN-CVE-2026-98524](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98524.md) | Oct 19, 2026 |
| Linux | linux Debian 14 | 7.2.9-1 | [DEBIAN-CVE-2026-98524](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98524.md) | Oct 19, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.113-1~deb12u1 | [DEBIAN-CVE-2026-98524](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98524.md) | Oct 19, 2026 |

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Data as of 2026-11-08T00:53:09Z 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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