ipv6: mcast: use rcu_assign_pointer() for __rcu list updates
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 7 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: use rcu_assign_pointer() for __rcu list updates Several places in net/ipv6/mcast.c update RCU-protected lists (np->ipv6_mc_list, idev->mc_list, idev->mc_tomb) using direct pointer assignments instead of rcu_assign_pointer(): 1. In __ipv6_dev_mc_dec(), unlinking a group from idev->mc_list did: *map = ma->next; without rcu_assign_pointer() while concurrent readers traverse idev->mc_list locklessly under rcu_read_lock(). 2. In ipv6_sock_mc_drop() and __ipv6_sock_mc_close(), unlinking a group from np->ipv6_mc_list directly assigned *lnk = mc_lst->next and np->ipv6_mc_list = mc_lst->next without rcu_assign_pointer(), racing with lockless readers in inet6_mc_check(). 3. In __ipv6_sock_mc_join(), mc_lst->next was initialized to np->ipv6_mc_list via raw assignment before publishing mc_lst. 4. In mld_del_delrec() and __ipv6_dev_mc_inc(), __rcu source pointers passed into rcu_assign_pointer() lacked explicit dereference helpers. Fix these by consistently using rcu_assign_pointer() along with mc_dereference() / sock_dereference().
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.38 and later | 6.6.160, 6.12.114, 6.18.57, 7.2.7, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.38 and later Fixed in 6.6.160, 6.12.114, 6.18.57, 7.2.7, 7.3 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.160, 6.12.114, 6.18.57, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-98099
- 2026-10-03 Alias added: GHSA-5fxh-xwwm-73v4
- 2026-10-16 Fix available: Linux/[email protected], Linux/Linux@afca229b39acc2590976b3e4f6e0fe76cededc60 · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@0e3e3cec28c4d1bf29948da40b4e9e5d44f7852b, Linux/Linux@49d7e1b456ba2f3ee08b3e264d999c09992cde8e, Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-28 CVSS score added · NVD
- 2026-10-28 Weakness changed · NVD
- 2026-11-01 Affected versions changed · Red Hat
- 2026-11-01 CVSS score added · Red Hat
References
Patch 5
- https://git.kernel.org/stable/c/0e3e3cec28c4d1bf29948da40b4e9e5d44f7852b
- https://git.kernel.org/stable/c/49d7e1b456ba2f3ee08b3e264d999c09992cde8e
- https://git.kernel.org/stable/c/afca229b39acc2590976b3e4f6e0fe76cededc60
- https://git.kernel.org/stable/c/2e46b0c9fcf7e10b64ce1630b925f47918d1f7f6
- https://git.kernel.org/stable/c/0c8f56c583c3250408367880c98e4d6fbc929315
More Linux Kernel vulnerabilities
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- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-98099 · CVE Program
- CVE-2026-98099 · NVD
- FIRST EPSS
- GHSA-5fxh-xwwm-73v4 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98099 · Red Hat security data · CC BY 4.0
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