Kernel-level RCE in Linux networking stack (netfilter/flowtable) affects widespread systems and could disrupt enterprise infrastructure.
CVE-2026-72249
Linux netfilter flowtable IPIP headroom bug enables kernel remote code execution.
Is CVE-2026-72249 being exploited?
Not confirmed. CVE-2026-72249 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.52% probability of exploitation in the next 30 days.
How severe is CVE-2026-72249?
CVE-2026-72249 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-72249?
Yes. A fix has been recorded for CVE-2026-72249. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-72249 affect?
CVE-2026-72249 affects Linux kernel (netfilter flowtable, IPIP). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-72249?
Apply vendor kernel updates ASAP; if unavailable, disable netfilter flowtable or IPIP encapsulation as temporary mitigation.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via crafted IPIP packets causing headroom miscalculation and kernel memory corruption (panic or arbitrary code execution).
Immediate action required
- affected>= d30301ba4b07ac92eb38353a111833b009003170 and < ecb78fbb03d3f86e2e93767875e273308086a424
- affected>= d30301ba4b07ac92eb38353a111833b009003170 and < c328b90c17fc5fa7786503695152880b2afb9326
- affected6.19
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.