Linux Kernel up to 7.2.5 RDS include/linux/wait.h rds_cong_map_updated m_waitq race condition

CVSS Meta Temp Score
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CTI Interest Score
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9.5$0-$5k0.40

Summaryinfo

A vulnerability categorized as very critical has been discovered in Linux Kernel up to 7.2.5. This affects the function rds_cong_map_updated of the file include/linux/wait.h of the component RDS. Such manipulation of the argument m_waitq leads to race condition. This vulnerability is listed as CVE-2026-90081. The attack may be performed from remote. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 7.2.5. Affected by this issue is the function rds_cong_map_updated of the file include/linux/wait.h of the component RDS. The manipulation of the argument m_waitq with an unknown input leads to a race condition vulnerability. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-90081 since 09/11/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/17/2026).

Upgrading to version 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch 2a809d7896dbf18e1ecfbdd930f71c9fc298b16d/fa4b98e891fda28cc0638d809c6125ec63d8319d/0e169f6a2adeb17b5577ed7e8abd642465bb50ec/42884bd8b8fd023d6a610a695bd5ddd1d5dece17/a526214b9f0548ca0e53a6e0d1727d8ea9befc23/bf2b8130723efcb5b86c3ddb6317c3a9b2a9cfc5/281f9fda2e06d6c211bb365a5379ed2e05cc2e21/d4f484661961636eb90d287050959e613795f73a is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.270/5.15.221/6.1.188/6.6.157/6.12.110/6.18.52/7.2.6/7.3-rc1
Patch: 2a809d7896dbf18e1ecfbdd930f71c9fc298b16d/fa4b98e891fda28cc0638d809c6125ec63d8319d/0e169f6a2adeb17b5577ed7e8abd642465bb50ec/42884bd8b8fd023d6a610a695bd5ddd1d5dece17/a526214b9f0548ca0e53a6e0d1727d8ea9befc23/bf2b8130723efcb5b86c3ddb6317c3a9b2a9cfc5/281f9fda2e06d6c211bb365a5379ed2e05cc2e21/d4f484661961636eb90d287050959e613795f73a

Timelineinfo

09/11/2026 CVE reserved
09/17/2026 +6 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90081 (🔒)
GCVE (CVE): GCVE-0-2026-90081
GCVE (VulDB): GCVE-100-406568

Entryinfo

Created: 09/17/2026 18:50
Changes: 09/17/2026 18:50 (61)
Complete: 🔍
Cache ID: 216::103

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