CVE-2026-98101: Linux kernel · ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 2.0 Medium.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that switches the IPv6 multicast source filter updates to use copy-on-write RCU mechanisms, ensuring safe concurrent access. Users should apply the official kernel updates that include this fix. No additional mitigation is indicated by the vendor advisory.
Description
A vulnerability in the Linux kernel's IPv6 multicast source filter handling was resolved. The issue involved unsafe in-place mutation of source filter data structures without proper synchronization, leading to potential torn reads or inconsistent source entries during multicast packet reception. The fix involved switching to copy-on-write RCU updates to ensure safe concurrent access and updates.
References
- ubuntu.com/security/CVE-2026-98101 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98101 (opens in a new tab)
- git.kernel.org/stable/c/2c2091e2ee93049fc513ad1e6c99d8b6c809f467 (opens in a new tab)
- git.kernel.org/stable/c/20db91a052332ef5552bd2f651ffb9db911cf67b (opens in a new tab)
- git.kernel.org/stable/c/c073d1b070f171d206b19c98d71739a97f15b3f1 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-98101 (opens in a new tab)
- git.kernel.org/stable/c/ac51321d3b2391860a935820ebcf4d8b9bb16a8a (opens in a new tab)
- git.kernel.org/stable/c/dba00514bf668c26cb4900e9f0da84bf96bf065a (opens in a new tab)