# CVE-2026-90081: net/rds: use wq_has_sleeper() in rds_cong_map_updated()

CVE-2026-90081 is fixed in 57 products on 1 platform, first by DEBIAN-CVE-2026-90081, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-90081
- Priority: High
- CVSS: 7.8 (Important)
- EPSS: 0.0022
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-90081

## Description

In the Linux kernel, the following vulnerability has been resolved:  net/rds: use wq_has_sleeper() in rds_cong_map_updated()  rds_cong_map_updated() runs after a peer's congestion map has been rewritten (by rds_tcp_cong_recv() and rds_ib_cong_recv(), or the clear-all in the loopback and IB send-completion paths).  It bumps rds_cong_generation and then checks waitqueue_active() on map->m_waitq and on rds_poll_waitq to decide whether anyone needs waking.  atomic_inc() carries no ordering and waitqueue_active() is a plain load, so nothing orders the map and generation stores before the wait queue reads.  The waiters do the mirror image: rds_cong_wait() adds itself to m_waitq and then tests the port bit, and rds_poll() registers on rds_poll_waitq and then reads the generation.  That is the store-buffering pattern described above waitqueue_active() in include/linux/wait.h - the updater can observe an empty wait queue while the waiter still observes the port as congested, and no wake-up is issued.  rds_cong_wait() is an interruptible sleep with no timeout, so a sender blocked on a congested port stays blocked until the next congestion update from that peer arrives or a signal is delivered. A poll() waiter misses the map-updated notification the same way.  Use wq_has_sleeper(), which is waitqueue_active() preceded by the required full barrier, as rds_tcp_state_change() already does for the same pattern.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bpftool amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | bpftool-debuginfo amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | bpftool6.12 amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | bpftool6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-debuginfo amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-devel amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-headers amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-livepatch-6.1.188-233.385 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-livepatch-6.12.110-135.201 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel-livepatch-6.18.54-121.166 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel-modules-extra amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-modules-extra-common amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-tools amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-tools-debuginfo amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel-tools-devel amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | kernel6.12 amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-devel amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-headers amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-tools amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | kernel6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-devel amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-headers amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-tools amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | linux Debian 12.15 (bookworm) | 6.1.190-1 | [DEBIAN-CVE-2026-90081](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90081.md) | Sep 23, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-90081](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90081.md) | Sep 23, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-90081](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90081.md) | Sep 23, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-90081](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90081.md) | Sep 23, 2026 |
| Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | perf amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | perf-debuginfo amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | perf6.12 amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | perf6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | python3-perf amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | python3-perf-debuginfo amzn 2023 | 1:6.1.188-233.385.amzn2023 | [ALAS2023-2026-3197](https://patchblox.com/security/data/fix/linux/alas2023-2026-3197.md) | Nov 7, 2026 |
| Linux | python3-perf6.12 amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.110-135.201.amzn2023 | [ALAS2023-2026-3196](https://patchblox.com/security/data/fix/linux/alas2023-2026-3196.md) | Nov 7, 2026 |
| Linux | python3-perf6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |
| Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 |

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