System hang via recursive IGMP route locking
Published Sep 25, 2026 · Updated Sep 25, 2026
Deadlock in the IPv4 IGMP implementation in Linux allows local users to hang the system when multicast reporting traverses an XFRM route. The ip_check_mc_rcu function acquires im->lock during an RCU route lookup while the same CPU already holds pmc->lock in the IGMPv3 report path. Reachability requires a matching multicast XFRM policy and a privileged local context; the published reproducer is not remotely triggerable.
Summary
What happened
Deadlock in the IPv4 IGMP implementation in Linux allows local users to hang the system when multicast reporting traverses an XFRM route. The ip_check_mc_rcu function acquires im->lock during an RCU route lookup while the same CPU already holds pmc->lock in the IGMPv3 report path. Reachability requires a matching multicast XFRM policy and a privileged local context; the published reproducer is not remotely triggerable.
The record
- CVE
- CVE-2026-98103
- Published
- Sep 25, 2026
- Updated
- Sep 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 25, 2026CVE publishedPublication date reported by the CVE source.
- Sep 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=23d2b94043ca8835bd1e67749020e839f396a1c2 <2987ee196c88dbde0463dc87d5fb209c684e34a2
- Affected versionversion=23d2b94043ca8835bd1e67749020e839f396a1c2 <d3011d1f293478c730aa0870490afa145c37600e
- Affected versionversion=23d2b94043ca8835bd1e67749020e839f396a1c2 <e3206419bdb04e2087d8cc6be324df8639b3fac5
- Affected versionversion=23d2b94043ca8835bd1e67749020e839f396a1c2 <f5182dfad54277267a8cb0c004a9cd4cf35aeebb
- Affected versionversion=4.14.247 <4.15
- Affected versionversion=4.19.207 <4.20
- Affected versionversion=4.4.284 <4.5
- Affected versionversion=4768973dffed4d0126854514335ed4fe87bec1ab
- Affected versionversion=4.9.283 <4.10
- Affected versionversion=5.10.64 <5.11
- Affected versionversion=5.13.16 <5.14
- Affected versionversion=5.14.3 <5.15
- Affected versionversion=5.15
- Affected versionversion=5.4.145 <5.5
- Affected versionversion=78967749984cf3614de346c90f3e259ff8272735
- Affected versionversion=961447ff60291b91e27d5c32fa549c1411ad3b70
- Affected versionversion=b24065948ae6c48c9e20891f8cfe9850f1d748be
- Affected versionversion=d1a3c6d5925a8d00a32c5ef2d674dd9c0ce89c95
- Affected versionversion=d84708451d9041dff8a81e3718f821f12d2eb6c5
- Affected versionversion=ddd7e8b7b84836c584a284b98ca9bd7a348a0558
- Affected versionversion=e9924c4204ede999b0515fd31a370a1e27f676bc
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
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