ipvs: revalidate ihl to prevent out-of-bounds access
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: ipvs: revalidate ihl to prevent out-of-bounds access While the outer IP header is already pulled into the skb head, we must be careful and revalidate the embedded headers after reading them from the skb frags to prevent out-of-bounds access. One such place reported by Sashiko is ip_vs_nat_icmp() where local process can change the ihl field and after skb_ensure_writable() we can see larger value which is a problem for the ip_send_check(cih) calls. Add check to drop the packet if the ihl field is changed.
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
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.1.10, 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-2026-74747
- 2026-10-03 Alias added: GHSA-769p-7f5g-9f2g
- 2026-10-16 Fix available: Linux/[email protected], Linux/Linux@eb81c8e758f49e04391f77d9470a6232bb5f1c7a · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-21 Fix available: Linux/Linux@041b2303c8019394735c1f76c5138657bf660a7d, Linux/Linux@2512289cbf58706fd558e8fccea4e28003a2af54, Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@f55bb94946fb8ee6304590a731c39c1fbc3b28bc · CNA
- 2026-10-30 1 new reference · CNA
References
Other 6
- https://git.kernel.org/stable/c/f55bb94946fb8ee6304590a731c39c1fbc3b28bc
- https://git.kernel.org/stable/c/2512289cbf58706fd558e8fccea4e28003a2af54
- https://git.kernel.org/stable/c/041b2303c8019394735c1f76c5138657bf660a7d
- https://git.kernel.org/stable/c/eb81c8e758f49e04391f77d9470a6232bb5f1c7a
- https://git.kernel.org/stable/c/5365f012451fce2453f13a568dcb72ea534c1e4d
- https://git.kernel.org/stable/c/d93660df4dd1d116f608ada4a29a80a5d6f0a6ed
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Sources
- CVE-2026-74747 · CVE Program
- CVE-2026-74747 · NVD
- FIRST EPSS
- GHSA-769p-7f5g-9f2g · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74747 · Red Hat security data · CC BY 4.0
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