Answer in brief
CVE-2026-74743 records a Critical severity (CVSS 9.8) vulnerability in macvlan: inherit needed_headroom and needed_tailroom from lowerdev. 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.
CVSS is 9.8. 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 | >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <8cd90e850e434577bf6774778657d26d6995e53f || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <28afc87bd8da0b3348bbbd834c8a89e83712cf5e || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <8f6a05dbac05725e0786701eb04778c5bdbe4eaa || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <96fa90b74385b7f2b0d97251dd43d5ee6ca44668 || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <bc9a00fb78e32bccc39d763bfd13a450705bac5d || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <cef51860becd9700217c81732ca1eb1ea6ed6fe1 | 8cd90e850e434577bf6774778657d26d6995e53f, 28afc87bd8da0b3348bbbd834c8a89e83712cf5e, 8f6a05dbac05725e0786701eb04778c5bdbe4eaa, 96fa90b74385b7f2b0d97251dd43d5ee6ca44668, bc9a00fb78e32bccc39d763bfd13a450705bac5d, cef51860becd9700217c81732ca1eb1ea6ed6fe1 |
| Linux/Linuxgeneric | 2.6.23 | Not reported |
| Linux/Linuxgeneric | >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <c2ef3f134b069c54b9cc95cce1a16c38c4939336 || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <7b0eb3e0f363ca79a3af9efd2e87c6258f11da2b || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <8cd90e850e434577bf6774778657d26d6995e53f || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <28afc87bd8da0b3348bbbd834c8a89e83712cf5e || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <8f6a05dbac05725e0786701eb04778c5bdbe4eaa || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <96fa90b74385b7f2b0d97251dd43d5ee6ca44668 || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <bc9a00fb78e32bccc39d763bfd13a450705bac5d || >=b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 <cef51860becd9700217c81732ca1eb1ea6ed6fe1 | c2ef3f134b069c54b9cc95cce1a16c38c4939336, 7b0eb3e0f363ca79a3af9efd2e87c6258f11da2b, 8cd90e850e434577bf6774778657d26d6995e53f, 28afc87bd8da0b3348bbbd834c8a89e83712cf5e, 8f6a05dbac05725e0786701eb04778c5bdbe4eaa, 96fa90b74385b7f2b0d97251dd43d5ee6ca44668, bc9a00fb78e32bccc39d763bfd13a450705bac5d, cef51860becd9700217c81732ca1eb1ea6ed6fe1 |
Published upstream
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 26, 2026
In the Linux kernel, the following vulnerability has been resolved: macvlan: inherit needed_headroom and needed_tailroom from lowerdev macvlan devices inherit hard_header_len from lowerdev during macvlan_init(), but leave needed_headroom and needed_tailroom set to 0. When the underlying lowerdev requires extra headroom or tailroom for headers/trailers (e.g. macsec, ipsec, wireguard, tunnels, or veth with rx headroom), upper layers calculating packet headroom and tailroom fail to reserve sufficient space. This can result in reallocation overhead, skb headroom underflows, or KASAN slab-use-after-free crashes when dev_hard_header() / macvlan_hard_header() prepends header data or when lower devices append tailroom. Fix this by: 1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init(). 2. Propagating needed_headroom and needed_tailroom updates to attached macvlans in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events.
Quoted source text, attributed separately from HOL analysis.