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CVE-2026-46244

CRITICALCVSS 9.1/10EPSS 0.39%

Last modified

CVE-2026-46244 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_inner: Fix IPv6 inner_thoff desync In nft_inner_parse_l2l3(), when processing inner IPv6 packets, ipv6_find_hdr() correctly computes the transport header offset traversing all extension headers, but the result is immediately overwritten with nhoff + sizeof(_ip6h) (40 bytes), which only accounts for the IPv6 base header. This creates a desync between inner_thoff (wrong — points to extension header start) and l4proto (correct — e.g., IPPROTO_TCP), enabling transport header forgery and potential firewall bypass. EPSS estimates a 0.39% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_inner: Fix IPv6 inner_thoff desync In nft_inner_parse_l2l3(), when processing inner IPv6 packets, ipv6_find_hdr() correctly computes the transport header offset traversing all extension headers, but the result is immediately overwritten with nhoff + sizeof(_ip6h) (40 bytes), which only accounts for the IPv6 base header. This creates a desync between inner_thoff (wrong — points to extension header start) and l4proto (correct — e.g., IPPROTO_TCP), enabling transport header forgery and potential firewall bypass. This issue affects stable versions from Linux 6.2. For comparison, the normal (non-inner) IPv6 path correctly preserves ipv6_find_hdr()'s result. Removing the incorrect overwrite ensures that ipv6_find_hdr()'s calculated transport header offset is preserved, thereby fixing the desynchronization.

Metrics

CVSS 3.1
9.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Probability
0.39%

31.0th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel>= 6.2, < 6.6.142—
LinuxLinux Kernel>= 6.7, < 6.12.92—
LinuxLinux Kernel>= 6.13, < 6.18.34—
LinuxLinux Kernel>= 6.19, < 7.0.11—
LinuxLinux Kernel7.1Rc1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-46244?
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_inner: Fix IPv6 inner_thoff desync In nft_inner_parse_l2l3(), when processing inner IPv6 packets, ipv6_find_hdr() correctly computes the transport header offset traversing all extension headers, but the result is immediately overwritten with nhoff + sizeof(_ip6h) (40 bytes), which only accounts for the IPv6 base header. This creates a desync between inner_thoff (wrong — points to extension header start) and l4proto (correct — e.g., IPPROTO_TCP), enabling transport header forgery and potential firewall bypass. This issue affects stable versions from Linux 6.2. For comparison, the normal (non-inner) IPv6 path correctly preserves ipv6_find_hdr()'s result. Removing the incorrect overwrite ensures that ipv6_find_hdr()'s calculated transport header offset is preserved, thereby fixing the desynchronization.
How severe is CVE-2026-46244?
CVE-2026-46244 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.39% probability of exploitation in the next 30 days.
How do I fix CVE-2026-46244?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-46244?

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Source: NVD / NIST