CVE-2026-97965 Affecting linux-6.12 package, versions <6.12.111-1~deb12u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-DEBIAN12-LINUX612-20507464
  • published5 Oct 2026
  • disclosed25 Sept 2026

Introduced: 25 Sep 2026

NewCVE-2026-97965  (opens in a new tab)

How to fix?

Upgrade Debian:12 linux-6.12 to version 6.12.111-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

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

vxlan: initialize _md in vxlan_xmit_one()

If a VXLAN device is configured with both VXLAN_F_COLLECT_METADATA and VXLAN_F_GBP, and a packet is transmitted through it using an external ip_tunnel_info that lacks the IP_TUNNEL_VXLAN_OPT_BIT flag, md is left pointing to the uninitialized _md stack variable:

            if (test_bit(IP_TUNNEL_VXLAN_OPT_BIT, info-&gt;key.tun_flags)) {
                    if (info-&gt;options_len &lt; sizeof(*md))
                            goto drop;
                    md = ip_tunnel_info_opts(info);
            }

Because IP_TUNNEL_VXLAN_OPT_BIT is not set, md is not updated and remains pointing to _md. Later, vxlan_build_skb() is called with md, which eventually calls vxlan_build_gbp_hdr():

    if (vxflags &amp; VXLAN_F_GBP)
            vxlan_build_gbp_hdr(vxh, md);

Inside vxlan_build_gbp_hdr(), md->gbp is read:

    if (!md-&gt;gbp)
            return;
    gbp = (struct vxlanhdr_gbp *)vxh;
    ...
    if (md-&gt;gbp &amp; VXLAN_GBP_DONT_LEARN)
            gbp-&gt;dont_learn = 1;

If the stack contains garbage, this causes:

  1. VXLAN_HF_GBP flag to be spuriously set in the VXLAN header.
  2. gbp->dont_learn and gbp->policy_applied to be set from stack bits.
  3. gbp->policy_id to receive 16 bits of uninitialized kernel stack data, leaking it onto the wire.

Fix this by zero-initializing _md. If IP_TUNNEL_VXLAN_OPT_BIT is not present, md->gbp remains 0, and vxlan_build_gbp_hdr() returns early without modifying the VXLAN header.

CVSS Base Scores

version 3.1