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major vulnerability· requires attention

Affects the Linux kernel's NFSv4.1 implementation used widely on servers and storage; can cause kernel memory corruption/DoS or RCE, risking broad infrastructure impact.

Systems

CVE-2026-90104

9.8
Critical
EPSS 0.68%Patch available

Linux NFSv4.1 kernel bug causing memory corruption via uninitialized callback lists.

exploited
No known exploitation not in CISA KEV as of our last sync
fix
Fixed in < 2.6.31, >= 7.2.6 and <= 7.2.*, >= 7.3-rc1 and <= *
likelihood
EPSS 0.68%top 48% of scored CVEs
Published 17 Sept 2026Analysed here 19 Sept 2026CVSS scored by the publisher (CNA)

do firstUpgrade to a fixed release: < 2.6.31, >= 7.2.6 and <= 7.2.*, >= 7.3-rc1 and <= *.

common questions

Is CVE-2026-90104 being exploited?

Not confirmed. CVE-2026-90104 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 0.68% probability of exploitation in the next 30 days.

How severe is CVE-2026-90104?

CVE-2026-90104 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-2026-90104?

Yes. A fix has been recorded for CVE-2026-90104. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-90104 affect?

CVE-2026-90104 affects Linux kernel with NFSv4.1 enabled, NFS clients and servers using callback sequences, Enterprise Linux distributions with affected kernels. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-90104?

Install vendor kernel update or apply the kernel patch; disable NFSv4.1 callbacks if unpatchable.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Linux kernel with NFSv4.1 enabledNFS clients and servers using callback sequencesEnterprise Linux distributions with affected kernels
impact

Remote kernel memory corruption via NFSv4.1 callback handling; can cause DoS (kernel panic) and potentially privilege escalation or RCE.

action required

Immediate action required

affected versions
Linux
  • affected>= 4aece6a19cf7f474f15eb861ba74db4479884ce3 and < f31f3c042e024aef437cda42f0424ae8d4594b6c
  • affected>= 4aece6a19cf7f474f15eb861ba74db4479884ce3 and < 8fa4804fe62ca4155a2d8fc2789d630376cbf2fc
  • affected2.6.31
vendor says fixed in< 2.6.31, >= 7.2.6 and <= 7.2.*, >= 7.3-rc1 and <= *

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.

timeline

  1. 17 Sept 2026Published
  2. 19 Sept 2026Analysed by vulneraibility.com · 2 days later
  3. 30 Oct 2026CVE record last updated · 41 days later
how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
NVDCVE.orgCVE DetailsSource
6 references in the CVE record: 6 links

sources

  • CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
  • NVD: CVSS and CPE data
  • FIRST EPSS: exploit probability and percentile
  • Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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