CVE-2026-43057
In the Linux kernel, the following vulnerability has been resolved: net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback NETIF_F_IPV6_CSUM only advertises support for checksum offload of packets without IPv6 extension headers.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.39%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback NETIF_F_IPV6_CSUM only advertises support for checksum offload of packets without IPv6 extension headers. Packets with extension headers must fall back onto software checksumming. Since TSO depends on checksum offload, those must revert to GSO. The below commit introduces that fallback. It always checks network header length. For tunneled packets, the inner header length must be checked instead. Extend the check accordingly. A special case is tunneled packets without inner IP protocol. Such as RFC 6951 SCTP in UDP. Those are not standard IPv6 followed by transport header either, so also must revert to the software GSO path.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.39% probability · 32th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/2094a7cf91b71367b649f991aacc7b579f793d0bPatch
- https://git.kernel.org/stable/c/33670f780e0120c3dacda188c512bbffe0b6044cPatch
- https://git.kernel.org/stable/c/732fdeb2987c94b439d51f5cb9addddc2fc48c42Patch
- https://git.kernel.org/stable/c/a98b78116a27e2a57b696b569b2cb431c95cf9b6Patch
- https://git.kernel.org/stable/c/c4336a07eb6b2526dc2b62928b5104b41a7f81f5Patch
- https://git.kernel.org/stable/c/ed71cf465c75f5688b07a35d373cd1d6b589c8eaPatch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.