packet: use consistent hard_header_len in TX_RING send path (CVE-2026-74668) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-74668

packet: use consistent hard_header_len in TX_RING send path

Answer in brief

CVE-2026-74668 records a Unknown severity vulnerability in packet: use consistent hard_header_len in TX_RING send path. The current sources do not mark it as known exploited. The current feed maps 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.

Published Aug 22, 2026Updated Aug 22, 2026Source checked Aug 22, 2026First seen by HOL Aug 22, 2026Material review Aug 22, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

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.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 <d85d2fd54e901637c81d847811e03c662aee13cd \|\| >=69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 <016763e829cac37b3234eace86fd0a4c560de4a7 \|\| >=69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 <27e068d1b35dbec10a3cf268887c94407be4badc \|\| >=69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 <d48ea5c9c4c34dc0df621f0e39ed3a16b644621a \|\| >=69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 <21b5953e7494c16a42e6cd8cf110e18d13ae4a6b	d85d2fd54e901637c81d847811e03c662aee13cd, 016763e829cac37b3234eace86fd0a4c560de4a7, 27e068d1b35dbec10a3cf268887c94407be4badc, d48ea5c9c4c34dc0df621f0e39ed3a16b644621a, 21b5953e7494c16a42e6cd8cf110e18d13ae4a6b
Linux/Linuxgeneric	2.6.31	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to d85d2fd54e901637c81d847811e03c662aee13cd if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 22, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: packet: use consistent hard_header_len in TX_RING send path tpacket_snd() reads dev->hard_header_len independently for skb allocation and header construction in tpacket_fill_skb(). Concurrent netdevice reconfiguration can therefore make the reserved headroom smaller than the amount later pushed, or make copylen - hard_header_len negative. Snapshot hard_header_len once before processing ring frames and use it for the frame limit, headroom allocation, copy length, and skb construction. Pass the snapshot to tpacket_fill_skb(). The separate SOCK_DGRAM consistency problem between hard_header_len and header_ops->create is not addressed here.

Quoted source text, attributed separately from HOL analysis.