ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 4 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: ip6_tunnel: clear skb2->cb[] in ip6ip6_err() ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the quoted inner IPv6 packet, and then passes the clone to icmpv6_send(). The clone still carries the outer packet's inet6_skb_parm in skb->cb. If the outer packet had a Home Address Option, IP6CB(skb2)->dsthao remains non-zero after skb_pull(). icmpv6_send() later calls mip6_addr_swap(), which uses that stale dsthao offset against the quoted inner packet. A malformed inner destination-options header can then make the HAO lookup and address swap run past the end of the quoted packet and corrupt skb_shared_info. Clear skb2->cb[] before pulling the quoted inner IPv6 packet so the reply path does not reuse metadata left by the outer IPv6 stack.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- 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 | 2.6.22 and later | 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.22 and later Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74597
- 2026-10-03 Alias added: GHSA-2fqw-fh97-qvmc
- 2026-10-18 CISA SSVC decision points changed
References
Other 8
- https://git.kernel.org/stable/c/44fe898df302e91c5ee5acbc71ffa74e78e6c183
- https://git.kernel.org/stable/c/0dadb0620ab65949a8bc2439dd28ea3c942fe87d
- https://git.kernel.org/stable/c/b6816536a2990c0db44a26130a03e40b441e829b
- https://git.kernel.org/stable/c/64e41736a26f37ab6215bc2e6df125df05aceb08
- https://git.kernel.org/stable/c/484134e1eb07d700a73b1e4bbf3fb503e299be60
- https://git.kernel.org/stable/c/4eb15c465337b18f44716c499cd6ad63eee0ad54
- https://git.kernel.org/stable/c/fbf40faa0414b753212494ad197542002e66ed9e
- https://git.kernel.org/stable/c/f803c086399da277b5d0ff36a107d0f162751800
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Sources
- CVE-2026-74597 · CVE Program
- CVE-2026-74597 · NVD
- FIRST EPSS
- GHSA-2fqw-fh97-qvmc · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74597 · 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