CVE-2026-97614

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: dsa: tag_brcm: 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 NETIF_F_SG and NETIF_F_FRAGLIST 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 dsa_loop test using this tagger reports:

BUG: KASAN: slab-out-of-bounds in crc32_le

Read of size 1 at addr ffff8880397086c0 by task exp/135

Call Trace:

crc32_le (lib/crc/crc32-main.c:38)

brcm_leg_fcs_tag_xmit (net/dsa/tag_brcm.c:343)

dsa_user_xmit (net/dsa/user.c:942)

dev_hard_start_xmit (net/core/dev.c:3937)

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References