UBUNTU-CVE-2026-97614: Medium severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: net: dsa: tagbrcm: legacy FCS: request needed tailroom The legacy FCS tagger calculates the CRC over skb->len bytes starting at skb->data. When a nonlinear skb reaches the tagger, this reads past the linear head into unrelated slab memory. The tagger appends an Ethernet FCS but does not declare that tailroom. As a result, DSA leaves NETIFFSG and NETIFFFRAGLIST enabled on the user port, and nonlinear skbs can reach the CRC calculation. Declare the required tailroom. DSA will then clear those features and the networking core will linearize skbs before the tagger runs. A KASAN-enabled dsaloop test using this tagger reports: BUG: KASAN: slab-out-of-bounds in crc32le Read of size 1 at addr ffff8880397086c0 by task exp/135 Call Trace: crc32le (lib/crc/crc32-main.c:38) brcmlegfcstagxmit (net/dsa/tagbrcm.c:343) dsauserxmit (net/dsa/user.c:942) devhardstartxmit (net/core/dev.c:3937) devqueuexmit (net/core/dev.c:4926) packetsendmsg (net/packet/afpacket.c:3110) syssendto (net/socket.c:2281) The buggy address belongs to the object at ffff888039708400 which belongs to the cache skbuffsmallhead of size 704 The buggy address is located 0 bytes to the right of allocated 704-byte region [ffff888039708400, ffff8880397086c0)