VulnerabilityPublished 9 Oct 2026Updated 30 Oct 2026

CVE-2026-98377: Linux kernel · vlan: require the MAC header to be present in __vlan_insert_inner_tag()

Source GCVE Database

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Authoritative record:CVE-2026-98377· High

Not known to be exploited · fixed in f42562dd027dc4ed103fae17b2206e73ea1963c4 : patch Linux kernel soon.

Data as of 30 Oct 2026, 17:18 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in f42562dd027dc4ed103fae17b2206e73ea1963c4, aecace4ef31bd4e8ca1f224280ab52a457b0dc9a, ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a +5

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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.

ghsa-jjqx-7ghh-p62x

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < f42562dd027dc4ed103fae17b2206e73ea1963c4	Fixed in f42562dd027dc4ed103fae17b2206e73ea1963c4
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < aecace4ef31bd4e8ca1f224280ab52a457b0dc9a	Fixed in aecace4ef31bd4e8ca1f224280ab52a457b0dc9a
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a	Fixed in ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 12295e0728488105b152b57fe8bc5e86f1d21a73	Fixed in 12295e0728488105b152b57fe8bc5e86f1d21a73
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc	Fixed in 59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 50a958f865173e8752ff07bf0eff7b55cdeb5d74	Fixed in 50a958f865173e8752ff07bf0eff7b55cdeb5d74

AI-suggested

A fix has been implemented that requires the MAC header to be present before VLAN tag insertion, causing frames without the MAC header to be dropped rather than transmitted. Users should apply the official Linux kernel update containing this fix once available. No other mitigation steps are indicated.

Description

A vulnerability in the Linux kernel's VLAN tag insertion function (__vlan_insert_inner_tag) allows uninitialized memory to be transmitted when the MAC header is not present. This occurs because the function assumes the presence of the MAC header and rewrites bytes without verifying its existence, potentially leaking kernel slab memory in transmitted packets.

References

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