CVE-2026-100070: Linux kernel · netfilter: nf_nat_sip: rewind offset when NAT shrinks the packet
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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 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 for this vulnerability has been implemented in the Linux kernel. Users should apply the official kernel updates that resolve this issue. Since this is a kernel-level vulnerability, upgrading to a patched kernel version is the recommended remediation. No vendor advisory or patch link was provided in the input, so verify with the Linux kernel or distribution vendor for the exact patched versions and update accordingly.
Description
A medium severity vulnerability in the Linux kernel's netfilter nf_nat_sip module was resolved. The issue occurs when NAT modifies the packet length, causing an offset pointer to become incorrect if the packet shrinks. This can lead to skipping bytes and missing subsequent Contact headers during SIP header parsing, potentially causing NAT to fail on those headers and possibly leaking internal network details.
References
- ubuntu.com/security/CVE-2026-100070 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-100070 (opens in a new tab)
- git.kernel.org/stable/c/c408d416618ebb8a95e3097a13f3b793ea9272ee (opens in a new tab)
- git.kernel.org/stable/c/16aecbe3036f6097c26b51b12e4c1cf207769690 (opens in a new tab)
- git.kernel.org/stable/c/0f4d30e2e49f343fc28ba1e259fd22969b940c46 (opens in a new tab)
- git.kernel.org/stable/c/810da5a63549531da78348b0a4545042d84e01e2 (opens in a new tab)
- git.kernel.org/stable/c/668cc1c30caedc63070b10d17d5514748988a140 (opens in a new tab)
- git.kernel.org/stable/c/6828aca3d82717c2fda92af81c0dda642bc2b465 (opens in a new tab)
- git.kernel.org/stable/c/2703f5ea8d85bc729f433ac09ee902084c947122 (opens in a new tab)
- git.kernel.org/stable/c/e70d48fcf8382581162608a4a322919bfd22aef3 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-100070.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)