CVE-2026-89561: Linux kernel · ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 15:59 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 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 adds a NULL check for the idev pointer in the ipv6_rthdr_rcv() function, preventing the NULL dereference in ipv6_rpl_srh_rcv(). Users should apply the updated Linux kernel versions that include this patch. No additional mitigations are indicated by the vendor advisory.
Description
A NULL pointer dereference vulnerability in the Linux kernel's IPv6 RPL implementation (ipv6_rpl_srh_rcv function) has been resolved. The flaw occurs when the idev pointer is dereferenced without a NULL check, leading to a kernel crash (KASAN null-ptr-deref) under specific conditions involving MTU changes and ping6 traffic flooding. The issue is fixed by adding a NULL check for idev in the ipv6_rthdr_rcv function before calling the affected functions, preventing the dereference and dropping the packet safely.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89561 (opens in a new tab)
- git.kernel.org/stable/c/63f50e9f90d0287ad66a0955ebfc2d3a9c044a1c (opens in a new tab)
- git.kernel.org/stable/c/eab3a917cdcb182542a3aac6a0d2d30659ca9821 (opens in a new tab)
- git.kernel.org/stable/c/f826df95332c07380206dbd54178b6eefb311aba (opens in a new tab)
- ubuntu.com/security/CVE-2026-89561 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89561 (opens in a new tab)
- git.kernel.org/linus/f826df95332c07380206dbd54178b6eefb311aba (opens in a new tab)