CVE-2026-72021
Linux ipvs SCTP IPv6 header parsing bug misclassifies connection state
Is CVE-2026-72021 being exploited?
Not confirmed. CVE-2026-72021 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 0.59% probability of exploitation in the next 30 days.
How severe is CVE-2026-72021?
CVE-2026-72021 is rated High with a CVSS score of 8.2. 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-2026-72021?
Yes. A fix has been recorded for CVE-2026-72021. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-72021 affect?
CVE-2026-72021 affects Linux kernel (ipvs module), IPVS-based load balancers, Kubernetes kube-proxy (IPVS mode), Telecom systems using SCTP over IPv6. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-72021?
Apply kernel/ipvs updates, restart IPVS/kube-proxy, monitor SCTP/IPv6 traffic
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Crafted IPv6 SCTP packets can cause IPVS to mark connections ESTABLISHED, extend timeouts and skew counters, enabling load‑balancer evasion or resource misuse.
Patch when possible
- affected>= 2906f66a5682e5670a5eefe991843689b8d8563f and < d2b8b1557ec07ea1bb5dddbceaf4dfe63d388e27
- affected>= 2906f66a5682e5670a5eefe991843689b8d8563f and < 9f94573ab962a9e81954b755da016fa3cd2f5039
- affected>= 2906f66a5682e5670a5eefe991843689b8d8563f and < 290e9e8389b556efc603522e28bd1543846aa336
- affected>= 2906f66a5682e5670a5eefe991843689b8d8563f and < 9cb5ac594ca76d3a71803b23b74c835b0721e628
- affected>= 2906f66a5682e5670a5eefe991843689b8d8563f and < a4a2d2e483d79cc2ad3a170674cf159644acf22b
- affected>= 2906f66a5682e5670a5eefe991843689b8d8563f and < 247d055504dcc852e539b9f7f30d19f9741474bf
- affected>= 2906f66a5682e5670a5eefe991843689b8d8563f and < e5d0bb8871668f20de8f3c94b5ae3f372346bc6e
- affected>= 2906f66a5682e5670a5eefe991843689b8d8563f and < 2f75c0faa3361b28e36cc0512b3299e163e25789
- affected2.6.34
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.