CVE-2026-43083: Linux kernel · net: ioam6: fix OOB and missing lock
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical · fixed in 6.17.0-1019.19~24.04.1 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.17.0-1019.19~24.04.1, 6.17.0-1020.22~24.04.1, 6.17.0-40.40~24.04.1 +12
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 May 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
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde@7.0.0-1008.8?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-nvidiapkg:deb/ubuntu/linux-nvidia@7.0.0-1006.6?arch=source&distro=resoluteOther threats | 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– |
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 promptly. Ubuntu has released updated Linux kernel packages (e.g., linux-image-6.17.0-1018-oracle 6.17.0-1018.18 and others) that fix this vulnerability. After applying the update, a system reboot is required to activate the fixes. Due to an ABI change in the kernel update, all third-party kernel modules must be recompiled and reinstalled. Follow the vendor's official advisories USN-8490-1 and USN-8491-1 for detailed update instructions. No additional mitigations are specified by the vendor.
Description
A high severity vulnerability (CVE-2026-43083) in the Linux kernel's ioam6 networking code could lead to out-of-bounds memory access and missing locking, potentially causing system instability or denial of service. The flaw occurs when processing packets on the RX path if the ingress device has more RX queues than the egress device has TX queues, leading to an unchecked index access. This issue has been fixed in Linux kernel versions 6.17.0-1026.26 and later. Ubuntu has released security updates addressing this and other kernel vulnerabilities, requiring a system reboot and recompilation of third-party kernel modules due to ABI changes.
References
- ubuntu.com/security/CVE-2026-43083 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-43083 (opens in a new tab)
- git.kernel.org/linus/b30b1675aa2bcf0491fd3830b051df4e08a7c8ca (opens in a new tab)
- ubuntu.com/security/notices/USN-8490-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8491-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8508-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8490-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8545-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8546-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8604-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8605-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8630-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8630-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8630-3 (opens in a new tab)