dlm: fix add msg handle in send_queue ordered
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: dlm: fix add msg handle in send_queue ordered In a benchmark scenario triggering a lot of requests that triggers a lot of DLM messages on the network it can be that the mh->seq is not ordered according the oldest seq number. This ordering is required by dlm_receive_ack as "before(mh->seq, seq)" will stop to check for older sequence numbers that are ordered in the tail of "node->send_queue". The side effects of not having it correct ordered regarding "before(mh->seq, seq)" are refcounting issues and use-after free. I only was able to reproduce this issue in a experimental DLM branch and a user space DLM benchmark that uses io_uring. After changing this I don't experienced any refcounting with the sending buffer issues anymore.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 3 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74401
- 2026-10-03 Alias added: GHSA-wgc9-j6gh-934m
- 2026-10-14 EPSS moved to the 50th–90th percentile
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-26 CVSS score changed · Red Hat
- 2026-10-30 Fix available: Linux/Linux@482606fea302d8bab86901d7426c3716980d99a8, Linux/[email protected] · CNA
- 2026-10-30 1 new reference · CNA
References
Other 6
- https://git.kernel.org/stable/c/482606fea302d8bab86901d7426c3716980d99a8
- https://git.kernel.org/stable/c/ae9e534e502a0f48c12baf83608c5de0ff0eab11
- https://git.kernel.org/stable/c/6369619f1b665f12d8c99cc6ff733c64eb08b22e
- https://git.kernel.org/stable/c/712714f818d83373847874ab0f8e426be79296cf
- https://git.kernel.org/stable/c/4d45250b1d22960f86d83245be188b16e456218b
- https://git.kernel.org/stable/c/d2248cb70c070f8f04762872772e155b59016f17
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Sources
- CVE-2026-74401 · CVE Program
- CVE-2026-74401 · NVD
- FIRST EPSS
- GHSA-wgc9-j6gh-934m · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74401 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences