# CVE-2026-98257: rds: ib: use rds_conn_drop() on protocol version mismatch

CVE-2026-98257 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-98257, released October 6, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-98257
- Priority: High
- CVSS: 7.5 (Moderate)
- EPSS: 0.0050
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 6, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98257

## Description

In the Linux kernel, the following vulnerability has been resolved:  rds: ib: use rds_conn_drop() on protocol version mismatch  rds_ib_cm_connect_complete() runs from the RDMA-CM event handler with conn->c_cm_lock held.  When the peer negotiates a protocol version older than RDS_PROTOCOL_COMPAT_VERSION, the handler calls rds_conn_destroy(), which is only safe in the rmmod path: it synchronously tears the connection down and flush_work()es the shutdown work cp_down_w.  That shutdown work (rds_conn_shutdown()) needs cp_cm_lock, which is the very lock the event handler still holds, so the flush never completes: the two workers wait on each other and the RDS connection workqueues stall for good.  All other RDMA-CM failure paths (REJECTED, CONNECT_ERROR, DISCONNECTED) use rds_conn_drop(), which marks the connection RDS_CONN_ERROR and schedules the shutdown work asynchronously.  Use it here as well.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.190-1 | [DEBIAN-CVE-2026-98257](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98257.md) | Oct 6, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.113-1 | [DEBIAN-CVE-2026-98257](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98257.md) | Oct 6, 2026 |
| Linux | linux Debian 14 | 7.2.8-1 | [DEBIAN-CVE-2026-98257](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98257.md) | Oct 6, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.113-1~deb12u1 | [DEBIAN-CVE-2026-98257](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98257.md) | Oct 6, 2026 |

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Data as of 2026-11-09T01:18:40Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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