packet: use consistent hard_header_len in TX_RING send path
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.31 and later | 5.10.267, 5.15.218, 6.1.185, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.31 and later Fixed in 5.10.267, 5.15.218, 6.1.185, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.267, 5.15.218, 6.1.185, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74668
- 2026-10-03 Alias added: GHSA-j5cf-5xp4-r57f
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-26 Affected versions changed · Red Hat
- 2026-10-26 CVSS score changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/9c7e8ff48c377bef18c3d178748aea0575b69ede
- https://git.kernel.org/stable/c/2a73b2c37ee3060a880b53cd24783d93fc7be5f8
- https://git.kernel.org/stable/c/e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2
- https://git.kernel.org/stable/c/d85d2fd54e901637c81d847811e03c662aee13cd
- https://git.kernel.org/stable/c/016763e829cac37b3234eace86fd0a4c560de4a7
- https://git.kernel.org/stable/c/27e068d1b35dbec10a3cf268887c94407be4badc
- https://git.kernel.org/stable/c/d48ea5c9c4c34dc0df621f0e39ed3a16b644621a
- https://git.kernel.org/stable/c/21b5953e7494c16a42e6cd8cf110e18d13ae4a6b
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Sources
- CVE-2026-74668 · CVE Program
- CVE-2026-74668 · NVD
- FIRST EPSS
- GHSA-j5cf-5xp4-r57f · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74668 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences