CVE-2021-47001: linux kernel — Fix

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().

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CVSS v3.1 Score

4.7

MEDIUM

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.5 — 5.10.38
linux	linux_kernel	5.11 — 5.11.22
linux	linux_kernel	5.12 — 5.12.5

References

Advisories & Patches

https://git.kernel.org/stable/c/19b5fa9489b5706bc878c3a522a7f771079e2fa0 https://git.kernel.org/stable/c/35d8b10a25884050bb3b0149b62c3818ec59f77c https://git.kernel.org/stable/c/8834ecb5df22b7ff3c9b0deba7726579bb613f95 https://git.kernel.org/stable/c/eddae8be7944096419c2ae29477a45f767d0fcd4 https://git.kernel.org/stable/c/19b5fa9489b5706bc878c3a522a7f771079e2fa0 https://git.kernel.org/stable/c/35d8b10a25884050bb3b0149b62c3818ec59f77c https://git.kernel.org/stable/c/8834ecb5df22b7ff3c9b0deba7726579bb613f95 https://git.kernel.org/stable/c/eddae8be7944096419c2ae29477a45f767d0fcd4

Other References

https://security.netapp.com/advisory/ntap-20250411-0001/

Frequently Asked Questions

What is CVE-2021-47001? +

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(). It has a CVSS v3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2021-47001? +

CVE-2021-47001 has a CVSS v3.1 score of 4.7 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2021-47001? +

CVE-2021-47001 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47001? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2021-47001