CVE-2026-100070
Published Sep 25, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_nat_sip: rewind offset when NAT shrinks the packet sashiko says: If map_addr() changes the packet length, such as when the public NAT IP string is shorter or longer than the internal IP, coff will still point to the offset relative to the pre-mangled packet. If the packet shrinks, coff could overshoot the correct position, potentially causing the next ct_sip_parse_header_uri() call to silently skip bytes and miss subsequent Contact headers. Could this lead to a failure to NAT those subsequent headers and leak internal network details?
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References
Other References
https://git.kernel.org/stable/c/0f4d30e2e49f343fc28ba1e259fd22969b940c46
https://git.kernel.org/stable/c/16aecbe3036f6097c26b51b12e4c1cf207769690
https://git.kernel.org/stable/c/2703f5ea8d85bc729f433ac09ee902084c947122
https://git.kernel.org/stable/c/668cc1c30caedc63070b10d17d5514748988a140
https://git.kernel.org/stable/c/6828aca3d82717c2fda92af81c0dda642bc2b465
https://git.kernel.org/stable/c/810da5a63549531da78348b0a4545042d84e01e2
https://git.kernel.org/stable/c/c408d416618ebb8a95e3097a13f3b793ea9272ee
https://git.kernel.org/stable/c/e70d48fcf8382581162608a4a322919bfd22aef3
Frequently Asked Questions
What is CVE-2026-100070? +
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_nat_sip: rewind offset when NAT shrinks the packet
sashiko says:
If map_addr() changes the packet length, such as when the public NAT IP
string is shorter or longer than the internal IP, coff will still point to
the offset relative to the pre-mangled packet.
If the packet shrinks, coff could overshoot the correct position,
potentially causing the next ct_sip_parse_header_uri() call to silently
skip bytes and miss subsequent Contact headers. Could this lead to a
failure to NAT those subsequent headers and leak internal network details?
How do I check if I'm vulnerable to CVE-2026-100070? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.