Affects the Linux kernel's SUNRPC GSS path used widely (NFS/RPC); remote crash or RCE can disrupt enterprise infrastructure and services.
CVE-2026-89550
Linux kernel SUNRPC GSS token length bug allows kernel crash or remote code execution
Is CVE-2026-89550 being exploited?
Not confirmed. CVE-2026-89550 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 0.46% probability of exploitation in the next 30 days.
How severe is CVE-2026-89550?
CVE-2026-89550 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-2026-89550?
Yes. A fix has been recorded for CVE-2026-89550. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89550 affect?
CVE-2026-89550 affects Linux kernel (svcauth_gss/SUNRPC), NFS servers using krb5/GSS, Any service accepting RPC GSS tokens. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89550?
Apply vendor Linux kernel updates ASAP; restrict/block RPC/GSS ingress until patched
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Malformed Kerberos GSS token via RPC can trigger a divide-by-zero in kernel crypto path, causing crash or potential remote code execution.
Immediate action required
- affected>= 7c9fdcfb1b64c47ed618c103b617af3f86e1239c and < dd6afc6cab8c5d387d1ed2f069562ef7bdadd651
- affected>= 7c9fdcfb1b64c47ed618c103b617af3f86e1239c and < de942dd8c2c8358bcad04ce44271954c48924423
- affected>= 7c9fdcfb1b64c47ed618c103b617af3f86e1239c and < 2eed1e6a976a44015c3ee78841fe336796e2b21c
- affected>= 7c9fdcfb1b64c47ed618c103b617af3f86e1239c and < a919c5c88769cf8fb3ec071e6078d830bf512489
- affected2.6.18
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.