CVE-2026-23304: Linux kernel · ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · patch available : update Linux kernel when convenient.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Mar 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 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1018.18?arch=source&distro=questingOther 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 patch is available and should be applied to affected linux-azure kernel versions to fix the NULL pointer dereference. The vendor advisory confirms the issue is resolved in updated kernel releases. Users should update to the fixed kernel versions listed in the advisory.
Description
A NULL pointer dereference vulnerability in the Linux kernel's IPv6 routing code (ip6_rt_get_dev_rcu) was fixed. The issue occurs when the function l3mdev_master_dev_rcu() returns NULL during the un-slaving of a slave device from a VRF, causing a NULL pointer dereference in ip6_rt_pcpu_alloc(). This flaw could lead to a denial of service (kernel crash). The vulnerability affects specific linux-azure kernel versions and has a medium severity score of 5.5. A patch is available to address this issue.
References
- ubuntu.com/security/CVE-2026-23304 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23304 (opens in a new tab)
- git.kernel.org/linus/2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a (opens in a new tab)
- git.kernel.org/stable/c/0b5a7826020706057cc5a9d9009e667027f221ee (opens in a new tab)
- git.kernel.org/stable/c/2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a (opens in a new tab)
- git.kernel.org/stable/c/3310fc11fc47387d1dd4759b0bc961643ea11c7f (opens in a new tab)
- git.kernel.org/stable/c/4a48fe59f29f673a3d042d679f26629a9c3e29d4 (opens in a new tab)
- git.kernel.org/stable/c/581800298313c9fd75e94985e6d37d21b7e35d34 (opens in a new tab)
- git.kernel.org/stable/c/ae88c8256547b63980770a9ea7be73a15900d27e (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8597-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-2 (opens in a new tab)