CVE-2026-98101ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()
- —Not scoredno CVSS score yet
- 0.17%Exploitation in 30 daysEPSS · top 94% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Linux
Published
- 24 days later
· 24 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Undergoing Analysis.
- EPSS (exploitation in 30 days)
- 0.17% · top 94% of all CVEs (15 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 882ba1f73c06831f2a21044ebd8864c485ac04f2 – < ac51321d3b2391860a935820ebcf4d8b9bb16a8a
- affected 882ba1f73c06831f2a21044ebd8864c485ac04f2 – < dba00514bf668c26cb4900e9f0da84bf96bf065a
- affected 882ba1f73c06831f2a21044ebd8864c485ac04f2 – < 2c2091e2ee93049fc513ad1e6c99d8b6c809f467
- affected 882ba1f73c06831f2a21044ebd8864c485ac04f2 – < 20db91a052332ef5552bd2f651ffb9db911cf67b
- affected 882ba1f73c06831f2a21044ebd8864c485ac04f2 – < c073d1b070f171d206b19c98d71739a97f15b3f1
- affected 47c75e3923c8d562fea8daf0ccf31546a7bef0ea
- affected 5.10.261 – < 5.11
- affected 5.13
- unaffected < 5.13
- unaffected 6.6.158 – ≤ 6.6.*
- unaffected 6.12.112 – ≤ 6.12.*
- unaffected 6.18.53 – ≤ 6.18.*
- unaffected 7.2.7 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References5
- https://git.kernel.org/stable/c/ac51321d3b2391860a935820ebcf4d8b9bb16a8a (opens in a new tab)
- https://git.kernel.org/stable/c/dba00514bf668c26cb4900e9f0da84bf96bf065a (opens in a new tab)
- https://git.kernel.org/stable/c/2c2091e2ee93049fc513ad1e6c99d8b6c809f467 (opens in a new tab)
- https://git.kernel.org/stable/c/20db91a052332ef5552bd2f651ffb9db911cf67b (opens in a new tab)
- https://git.kernel.org/stable/c/c073d1b070f171d206b19c98d71739a97f15b3f1 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-86932 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-98101)Record last updated .