mptcp: pm: kernel: drop pending ADD_ADDR when removing ID0
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: kernel: drop pending ADD_ADDR when removing ID0 The in-kernel MPTCP path manager can leave a stale ADD_ADDR announcement entry alive when removing the id 0 endpoint. This happens because the id 0 removal path does not tear down pending announcements, unlike the non-zero id path. When the PM later reselects id 0 after adding another signal endpoint, it finds the stale anno_list entry and hits WARN_ON_ONCE(mptcp_pm_is_kernel()) in mptcp_pm_announced_alloc(). Root cause: asymmetry between removal paths. - Non-zero id path: mptcp_nl_remove_subflow_and_signal_addr() calls mptcp_pm_remove_announced() to clean up. - Id 0 path: mptcp_nl_remove_id_zero_address() skips cleanup entirely. Fix by making the id 0 path symmetric: call mptcp_pm_announced_remove() and decrement add_addr_signaled before queuing the RM_ADDR. Subtle detail: signal endpoints are stored in anno_list with port 0, but msk_local carries the connection's local port. In other words, entries linked to ID0 paths should have port == 0. A follow-up patch will ensure that. mptcp_pm_announced_remove() uses use_port=true for comparison. So clear the port before the lookup.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.112, 6.18.53, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
Not affected: 6 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-97566
- 2026-10-03 Alias added: GHSA-27x2-682m-9qm4
- 2026-10-03 Fix available: Linux/[email protected], Linux/Linux@bacf23e7c9876c9f4170166b3597cb22ea3ed39b · CNA
- 2026-10-03 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@189d60057e5f3d6a62e3d71a3cc428c9150bc14f, Linux/[email protected] · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-30 Fix available: Linux/Linux@4af59a98aead422a152d805a89586dbb65616fc8, Linux/[email protected] · CNA
- 2026-10-30 1 new reference · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 6
- https://git.kernel.org/stable/c/4af59a98aead422a152d805a89586dbb65616fc8
- https://git.kernel.org/stable/c/189d60057e5f3d6a62e3d71a3cc428c9150bc14f
- https://git.kernel.org/stable/c/bacf23e7c9876c9f4170166b3597cb22ea3ed39b
- https://git.kernel.org/stable/c/d4a67a880654e1bfe318a31bea0bdbb026a09ade
- https://git.kernel.org/stable/c/545616b4e7325be3c61fc082538cb06d14f7b1db
- https://git.kernel.org/stable/c/2ac7d6e620764f1fc79eb4edd3610a7a661981ca
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Sources
- CVE-2026-97566 · CVE Program
- CVE-2026-97566 · NVD
- FIRST EPSS
- GHSA-27x2-682m-9qm4 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-97566 · Red Hat security data · CC BY 4.0
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