Answer in brief
CVE-2026-46099 records a High severity (CVSS 8.1) vulnerability in net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels. The current sources do not mark it as known exploited. The current feed maps Red Hat/kernel (generic), Red Hat/kernel-rt (generic), Linux/Linux (generic), Linux/Linux (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Red Hat/kernel (generic), Red Hat/kernel-rt (generic), Linux/Linux (generic), Linux/Linux (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Red Hat/kernelgeneric | * | Not reported |
| Red Hat/kernel-rtgeneric | * | Not reported |
| Linux/Linuxgeneric | >=af4a2209b1344939eaac11f269c261d347cbc3ee <51fef5a7c4d160839199e941929456ba21ddf73c || >=af4a2209b1344939eaac11f269c261d347cbc3ee <b258b849a580285a1692e782ebc902b44c884a71 || >=af4a2209b1344939eaac11f269c261d347cbc3ee <6bd17925bd6866027a6555db17905b9fc073d38d || >=af4a2209b1344939eaac11f269c261d347cbc3ee <52f9db67f8f35f436366cf4980b4f0a2583d0ef0 || >=af4a2209b1344939eaac11f269c261d347cbc3ee <b778b6d095421619c331fd2d7751143cd5387103 || >=af4a2209b1344939eaac11f269c261d347cbc3ee <9dd5481f960e337b81d7dfe429529495c1c481c0 || >=af4a2209b1344939eaac11f269c261d347cbc3ee <f9c52a6ba9780bd27e0bf4c044fd91c13c778b6e | 51fef5a7c4d160839199e941929456ba21ddf73c, b258b849a580285a1692e782ebc902b44c884a71, 6bd17925bd6866027a6555db17905b9fc073d38d, 52f9db67f8f35f436366cf4980b4f0a2583d0ef0, b778b6d095421619c331fd2d7751143cd5387103, 9dd5481f960e337b81d7dfe429529495c1c481c0, f9c52a6ba9780bd27e0bf4c044fd91c13c778b6e |
| Linux/Linuxgeneric | 4.12 | Not reported |
| Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric | >=0 <* | * |
Published upstream
May 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 25, 2026
In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels seg6_input_core() and rpl_input() call ip6_route_input() which sets a NOREF dst on the skb, then pass it to dst_cache_set_ip6() invoking dst_hold() unconditionally. On PREEMPT_RT, ksoftirqd is preemptible and a higher-priority task can release the underlying pcpu_rt between the lookup and the caching through a concurrent FIB lookup on a shared nexthop. Simplified race sequence: ksoftirqd/X higher-prio task (same CPU X) ----------- -------------------------------- seg6_input_core(,skb)/rpl_input(skb) dst_cache_get() -> miss ip6_route_input(skb) -> ip6_pol_route(,skb,flags) [RT6_LOOKUP_F_DST_NOREF in flags] -> FIB lookup resolves fib6_nh [nhid=N route] -> rt6_make_pcpu_route() [creates pcpu_rt, refcount=1] pcpu_rt->sernum = fib6_sernum [fib6_sernum=W] -> cmpxchg(fib6_nh.rt6i_pcpu, NULL, pcpu_rt) [slot was empty, store succeeds] -> skb_dst_set_noref(skb, dst) [dst is pcpu_rt, refcount still 1] rt_genid_bump_ipv6() -> bumps fib6_sernum [fib6_sernum from W to Z] ip6_route_output() -> ip6_pol_route() -> FIB lookup resolves fib6_nh [nhid=N] -> rt6_get_pcpu_route() pcpu_rt->sernum != fib6_sernum [W <> Z, stale] -> prev = xchg(rt6i_pcpu, NULL) -> dst_release(prev) [prev is pcpu_rt, refcount 1->0, dead] dst = skb_dst(skb) [dst is the dead pcpu_rt] dst_cache_set_ip6(dst) -> dst_hold() on dead dst -> WARN / use-after-free For the race to occur, ksoftirqd must be preemptible (PREEMPT_RT without PREEMPT_RT_NEEDS_BH_LOCK) and a concurrent task must be able to release the pcpu_rt. Shared nexthop objects provide such a path, as two routes pointing to the same nhid share the same fib6_nh and its rt6i_pcpu entry. Fix seg6_input_core() and rpl_input() by calling skb_dst_force() after ip6_route_input() to force the NOREF dst into a refcounted one before caching. The output path is not affected as ip6_route_output() already returns a refcounted dst.
Quoted source text, attributed separately from HOL analysis.