CVE-2026-98103
igmp: convert struct ip_sf_list to RCU
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: igmp: convert struct ip_sf_list to RCU Commit 23d2b94043ca ("igmp: Add ip_mc_list lock in ip_check_mc_rcu") added spin_lock_bh(&im->lock) to ip_check_mc_rcu() to prevent a use-after-free while iterating im->sources during concurrent deletions. However, ip_check_mc_rcu() is called from RCU read-side critical sections in packet receive and route lookup fast paths (e.g. __mkroute_output(), ip_route_input_rcu(), and __udp4_lib_rcv()). When igmpv3_send_cr() or igmpv3_send_report() holds &pmc->lock and calls add_grec() -> igmpv3_newpack() -> ip_route_output_ports(), an XFRM policy matching a multicast destination triggers xfrm_tmpl_resolve_one() -> xfrm4_get_saddr() -> __mkroute_output() -> ip_check_mc_rcu(). This attempts to acquire &im->lock while &pmc->lock is already held on the same CPU, triggering a lockdep recursive locking warning / deadlock. Fix this by converting IPv4 struct ip_sf_list to RCU, mirroring the IPv6 implementation in net/ipv6/mcast.c: 1. Add struct rcu_head to struct ip_sf_list and annotate sf_next, sources, and tomb as __rcu pointers. 2. Use rcu_assign_pointer() and kfree_rcu() for list updates and deletions. 3. Remove spin_lock_bh(&im->lock) from ip_check_mc_rcu() and traverse im->sources locklessly with for_each_psf_rcu(), reading and writing counter fields with READ_ONCE() and WRITE_ONCE(). Note: RCU conversion of /proc/net/mcfilter will be done in a separate patch.
Timeline
ID reserved
By Linux
Published
- 26 days later
· 26 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 (8 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 23d2b94043ca8835bd1e67749020e839f396a1c2 – < 01131daffc4b64f1652e23dc3e6e2f601eda781d
- affected 23d2b94043ca8835bd1e67749020e839f396a1c2 – < f5182dfad54277267a8cb0c004a9cd4cf35aeebb
- affected 23d2b94043ca8835bd1e67749020e839f396a1c2 – < d3011d1f293478c730aa0870490afa145c37600e
- affected 23d2b94043ca8835bd1e67749020e839f396a1c2 – < e3206419bdb04e2087d8cc6be324df8639b3fac5
- affected 23d2b94043ca8835bd1e67749020e839f396a1c2 – < 2987ee196c88dbde0463dc87d5fb209c684e34a2
- affected b24065948ae6c48c9e20891f8cfe9850f1d748be
- affected e9924c4204ede999b0515fd31a370a1e27f676bc
- affected 78967749984cf3614de346c90f3e259ff8272735
- affected 4768973dffed4d0126854514335ed4fe87bec1ab
- affected d84708451d9041dff8a81e3718f821f12d2eb6c5
- affected ddd7e8b7b84836c584a284b98ca9bd7a348a0558
- affected 961447ff60291b91e27d5c32fa549c1411ad3b70
- affected d1a3c6d5925a8d00a32c5ef2d674dd9c0ce89c95
- affected 4.4.284 – < 4.5
- affected 4.9.283 – < 4.10
- affected 4.14.247 – < 4.15
- affected 4.19.207 – < 4.20
- affected 5.4.145 – < 5.5
- affected 5.10.64 – < 5.11
- affected 5.13.16 – < 5.14
- affected 5.14.3 – < 5.15
- affected 5.15
- unaffected < 5.15
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.111 – ≤ 6.12.*
- unaffected 6.18.53 – ≤ 6.18.*
- unaffected 7.2.7 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References (5)
- https://git.kernel.org/stable/c/01131daffc4b64f1652e23dc3e6e2f601eda781d (opens in a new tab)
- https://git.kernel.org/stable/c/f5182dfad54277267a8cb0c004a9cd4cf35aeebb (opens in a new tab)
- https://git.kernel.org/stable/c/d3011d1f293478c730aa0870490afa145c37600e (opens in a new tab)
- https://git.kernel.org/stable/c/e3206419bdb04e2087d8cc6be324df8639b3fac5 (opens in a new tab)
- https://git.kernel.org/stable/c/2987ee196c88dbde0463dc87d5fb209c684e34a2 (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)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-98103)Record last updated .