VulnerabilityPublished 25 Sep 2026Updated 21 Oct 2026

CVE-2026-97965: Linux kernel · vxlan: initialize _md in vxlan_xmit_one()

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in fb78beb64e0e79557e4cd7cd17fea744bb6f01d9 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in fb78beb64e0e79557e4cd7cd17fea744bb6f01d9, bfb74c48ac2d31476d5e09cf9658844508d2608a, be83178bfc44588f6e3adb827ed874c683193466 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ ee122c79d4227f6ec642157834b6a90fcffa4382, < fb78beb64e0e79557e4cd7cd17fea744bb6f01d9	Fixed in fb78beb64e0e79557e4cd7cd17fea744bb6f01d9
LinuxLinux	Affected ≥ ee122c79d4227f6ec642157834b6a90fcffa4382, < bfb74c48ac2d31476d5e09cf9658844508d2608a	Fixed in bfb74c48ac2d31476d5e09cf9658844508d2608a
LinuxLinux	Affected ≥ ee122c79d4227f6ec642157834b6a90fcffa4382, < be83178bfc44588f6e3adb827ed874c683193466	Fixed in be83178bfc44588f6e3adb827ed874c683193466
LinuxLinux	Affected ≥ ee122c79d4227f6ec642157834b6a90fcffa4382, < 081f22177d9d12b1e381b787f203cd5f47508187	Fixed in 081f22177d9d12b1e381b787f203cd5f47508187
LinuxLinux	Affected ≥ ee122c79d4227f6ec642157834b6a90fcffa4382, < 0d13b5a413bffc8718b3821b78537ccc6596c233	Fixed in 0d13b5a413bffc8718b3821b78537ccc6596c233
LinuxLinux	Affected =4.3	Fixed in–

Description

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->key.tun_flags)) { if (info->options_len < 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 & VXLAN_F_GBP) vxlan_build_gbp_hdr(vxh, md); Inside vxlan_build_gbp_hdr(), md->gbp is read: if (!md->gbp) return; gbp = (struct vxlanhdr_gbp *)vxh; ... if (md->gbp & VXLAN_GBP_DONT_LEARN) gbp->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.

References

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