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TI-2026-69880 Aliases CVE-2026-98377GHSA-jjqx-7ghh-p62x

Missing MAC header check in Linux kernel VLAN tag insertion

Priority LOW 22Published · Updated

Key facts

Attack vector
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Privileges required
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User interaction
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Attack complexity
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Impact type
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Confidentiality · integrity · availability
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Fix status
Partial Red Hat: 7 without a fix

No CVSS vector from any source. Fix status from CNA and Red Hat.

Summary

The Linux kernel from 2.6.12 fails to require the MAC header in __vlan_insert_inner_tag(), so the helper rewrites the first 16 bytes of a packet that may be too short. A one-byte frame sent through an IFF_TUN device can have uninitialised slab memory added to it through repeated VLAN tag pushes. The kernel then transmits that memory on the wire, leaking kernel data.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

In the Linux kernel, the following vulnerability has been resolved: vlan: require the MAC header to be present in __vlan_insert_inner_tag() __vlan_insert_inner_tag() only guarantees head room via skb_cow_head(), never that mac_len bytes of MAC header are present. Its ETH_HLEN wrappers - __vlan_insert_tag() under skb_vlan_push(), and vlan_insert_tag() under validate_xmit_vlan() on the generic transmit path - therefore rewrite the first 16 bytes at skb->data: a 12-byte memmove plus two 2-byte stores at +12 and +14. No caller supplies the bound, while the pop helpers use skb_ensure_writable()/pskb_may_pull(). An IFF_TUN device has hard_header_len == 0, so packet_snd() accepts a one-byte AF_PACKET/SOCK_RAW frame. The first vlan push only sets a hwaccel tag; the next - clsact "action vlan push" or bpf_skb_vlan_push() - enters the helper with skb->len still 1. The head comes from skbuff_small_head without __GFP_ZERO, so each push drags bytes from beyond skb->tail into the frame. After three the one-byte send leaves as 13 bytes carrying 11 bytes of uninitialised slab: 0000: 5a b3 62 12 80 88 ff ff 00 b3 62 12 81 `------------------------------' only 0x5a was sent; the rest is slab, here the top 56 bits of a linear-map address Require the MAC header the helper rewrites to be present, so such a frame is dropped rather than transmitted.

Why it matters now

EPSS 0.00171 6th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.273, 5.15.224, 6.1.191 +5Red Hat: 7 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux2.6.12 and later5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9, 7.3Patch availableCNA
  • Linux VendorLinux Affected 2.6.12 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9, 7.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

Upgrade the Linux kernel to 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9 or 7.3. Red Hat Enterprise Linux 6 has no fix planned, and Red Hat Enterprise Linux 7, 8, 9 and 10 and OpenShift Container Platform 4 and 5 have no fix available.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9, 7.3

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-09 Threatist record created from CVE-2026-98377
  2. 2026-10-09 Alias added: GHSA-jjqx-7ghh-p62x
  3. 2026-10-11 Affected versions changed · Red Hat
  4. 2026-10-11 CVSS score added · Red Hat
  5. 2026-10-19 Fix available: Linux/[email protected] · CNA
  6. 2026-10-21 Fix available: Linux/Linux@3d531429524df2c7116579306640283fea68bcf0, Linux/[email protected] · CNA
  7. 2026-10-21 1 new reference · CNA
  8. 2026-10-21 Affected versions changed · Red Hat
  9. 2026-10-21 CVSS score changed · Red Hat
  10. 2026-10-30 Fix available: Linux/Linux@12295e0728488105b152b57fe8bc5e86f1d21a73, Linux/[email protected], Linux/[email protected] +3 · CNA
  11. 2026-10-30 3 new references · CNA
  12. 2026-11-06 Affected versions changed · Red Hat

References

Other 8

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21727 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences