UBUNTU-CVE-2026-98098: Null Pointer Dereference
In the Linux kernel, the following vulnerability has been resolved: tipc: fix NULL deref in tipcnamednodeup() on empty publication list User-space applications can bind a large number of service addresses to one or more sockets. Each binding of a local-scope service address inserts one entry (publication) into the TIPC name table. If the number of these publications exceeds TIPCMAXPUBL (65535), protocol service types (such as node state and link state) are no longer inserted into the name table. This causes two issues: 1. User-space applications subscribing to node or link up/down events stop receiving notifications. 2. A NULL pointer dereference can occur: BUG: kernel NULL pointer dereference, address: 00000000000000d0 ... CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 7.2.0-rc4-default+ #5 PREEMPT(full) ... RIP: 0010:tipcnamednodeup (./include/linux/skbuff.h:2251 net/tipc/namedistr.c:195 net/tipc/namedistr.c:221) ... Call Trace: <IRQ> tipcnodewriteunlock (net/tipc/node.c:428) tipcrcv (net/tipc/node.c:934 net/tipc/node.c:2189) tipcudprecv (net/tipc/udpmedia.c:389) Thread 1 (tipcnetfinalize) | Thread 2 (nameddistribute) -----------------------------|----------------------------- | ... | listforeachentry(publ, pls, bindingnode) { | ... | skbqueuetail(list, skb); | ... | } | ... | hdr = bufmsg(skbpeektail(list)); ... | tipcnametblpublish(); | If 'tipcnametblpublish()' (Thread 1) fails because the number of local publications reaches TIPCMAXPUBL, list (Thread 2) will be empty. As a result, NULL is passed to 'bufmsg()', leading to a NULL pointer dereference. Fix these issues by allowing protocol service types (node state, link state, and topology server) to be inserted into the name table unconditionally. This ensures that users subscribing to these types always receive notifications. In addition, the maximum number of local user publications is reduced to (TIPCMAXPUBL - 1). This ensures that the maximum bulk size calculated in tipclinksetqueuelimits() remains valid.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linux-aws-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1119.126~20.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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