Answer in brief
CVE-2026-98101 records a Unknown severity vulnerability in ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. 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 Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=882ba1f73c06831f2a21044ebd8864c485ac04f2 <2c2091e2ee93049fc513ad1e6c99d8b6c809f467 || >=882ba1f73c06831f2a21044ebd8864c485ac04f2 <20db91a052332ef5552bd2f651ffb9db911cf67b || >=882ba1f73c06831f2a21044ebd8864c485ac04f2 <c073d1b070f171d206b19c98d71739a97f15b3f1 || 47c75e3923c8d562fea8daf0ccf31546a7bef0ea || >=5.10.261 <5.11 | 2c2091e2ee93049fc513ad1e6c99d8b6c809f467, 20db91a052332ef5552bd2f651ffb9db911cf67b, c073d1b070f171d206b19c98d71739a97f15b3f1, 5.11 |
| Linux/Linuxgeneric | 5.13 | Not reported |
Published upstream
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 25, 2026
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source() pmc->sflist is read locklessly under rcu_read_lock() by inet6_mc_check() during packet reception in the UDP and RAW multicast receive paths. ip6_mc_source() mutated psl->sl_addr and psl->sl_count in-place when adding or removing a source filter. Additionally, when expanding the filter buffer, newpsl was published via rcu_assign_pointer() before writing the new source into the array. Because 16-byte struct in6_addr writes are not atomic and array shifting is not synchronized with RCU readers, concurrent readers in inet6_mc_check() could read torn IPv6 addresses or observe duplicated/missed source entries. Fix this by switching ip6_mc_source() to copy-on-write RCU updates: allocate and fully populate newpsl before publishing it via rcu_assign_pointer(), and reclaim the old filter via kfree_rcu(), matching ip6_mc_msfilter(). Also remove the now unused IP6_SFBLOCK macro.
Quoted source text, attributed separately from HOL analysis.