Answer in brief
CVE-2026-98377 records a Unknown severity vulnerability in vlan: require the MAC header to be present in __vlan_insert_inner_tag(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <40a5cc4b7251c74f3341332a226d02200e96bccf || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f42562dd027dc4ed103fae17b2206e73ea1963c4 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a | 40a5cc4b7251c74f3341332a226d02200e96bccf, f42562dd027dc4ed103fae17b2206e73ea1963c4, 59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc, ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3d531429524df2c7116579306640283fea68bcf0 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <40a5cc4b7251c74f3341332a226d02200e96bccf || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f42562dd027dc4ed103fae17b2206e73ea1963c4 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a | 3d531429524df2c7116579306640283fea68bcf0, 40a5cc4b7251c74f3341332a226d02200e96bccf, f42562dd027dc4ed103fae17b2206e73ea1963c4, 59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdc, ab888242fce4f16f6c4d4c6ec53939ad36aa3b3a |
Published upstream
Oct 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 9, 2026
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.
Quoted source text, attributed separately from HOL analysis.