Linux kernel vulnerability enabling remote kernel compromise via SUNRPC/GSS Kerberos; impacts broad Linux deployments and NFS clients used across enterprises.
CVE-2026-89537
Linux kernel SUNRPC GSS Kerberos length bug allows remote kernel compromise
Is CVE-2026-89537 being exploited?
Not confirmed. CVE-2026-89537 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-2026-89537?
CVE-2026-89537 is rated Critical with a CVSS score of 9.1. 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-2026-89537?
Yes. A fix has been recorded for CVE-2026-89537. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89537 affect?
CVE-2026-89537 affects Linux kernel (SUNRPC gss_krb5), NFS clients using Kerberos/GSS, SUNRPC-based services. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89537?
Apply vendor/kernel updates containing the commit ASAP; avoid untrusted NFS servers.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Malicious NFS server can send crafted MIC tokens causing kernel OOB reads, enabling memory disclosure, crashes, or possible remote code execution.
Immediate action required
- affected>= de9c17eb4a912c9028f7b470eb80815144883b26 and < 7a946b2e7207f968902f2147ab9b30726f82f7ab
- affected>= de9c17eb4a912c9028f7b470eb80815144883b26 and < b94f6719dcd9f7a609bc5f459f85795900e77d25
- affected2.6.35
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.