# CVE-2021-47001: linux: In the Linux kernel, the following vulnerability has been resolved:  xprtrdma: Fix cwnd update ordering  After a reco...

CVE-2021-47001 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47001, released February 28, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47001
- Priority: Routine
- CVSS: 4.7 (medium)
- EPSS: 0.0075
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 28, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  xprtrdma: Fix cwnd update ordering  After a reconnect, the reply handler is opening the cwnd (and thus enabling more RPC Calls to be sent) /before/ rpcrdma_post_recvs() can post enough Receive WRs to receive their replies. This causes an RNR and the new connection is lost immediately.  The race is most clearly exposed when KASAN and disconnect injection are enabled. This slows down rpcrdma_rep_create() enough to allow the send side to post a bunch of RPC Calls before the Receive completion handler can invoke ib_post_recv().

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.10.38-1 | [DEBIAN-CVE-2021-47001](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47001.md) | Feb 28, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.10.38-1 | [DEBIAN-CVE-2021-47001](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47001.md) | Feb 28, 2024 |
| Linux | linux Debian 14 | 5.10.38-1 | [DEBIAN-CVE-2021-47001](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47001.md) | Feb 28, 2024 |

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Data as of 2026-11-09T13:31:49Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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