Is there a patch available for CVE-2026-99121?

Yes, a patch is available for CVE-2026-99121. Update the affected software to the latest version immediately.

Linux CVE-2026-99121

EUVD-2026-112021

2026-10-28 Linux

GHSA-6q9r-cqw9-q9q4

Information Disclosure Linux

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Awaiting Data No severity or threat signals available yet. Label will update when CVSS score is published or threat intelligence arrives.

Patch available

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AnalysisCVE.org

In the Linux kernel, the following vulnerability has been resolved:

ipv4: avoid divide by zero in fib_rebalance

fib_rebalance() computes the total eligible nexthop weight in one pass and programs upper bounds in a second pass. A concurrent change to ignore_routes_with_linkdown can make the first pass return zero while the second pass sees an eligible nexthop, resulting in division by zero.

If the first pass reports a zero total, set each nexthop upper bound to -1 and skip the division. This matches the IPv6 fix in commit d2c26c2911dd ("ipv6: avoid divide by zero in rt6_multipath_rebalance") and preserves the lock-free rebalance path.

Affected VersionsENISA

Linux 0e884c78ee19e902f300ed147083c28a0c6302f0 <5dac5c7ba8f5f3fb4bf29f2a2c3cb552f5b83c8f

Linux patch: 7.2.13

Linux 0e884c78ee19e902f300ed147083c28a0c6302f0 <d5520e815c4b1427104ce1428ee23821f2aa824d

Linux patch: 6.18.59

Linux 0e884c78ee19e902f300ed147083c28a0c6302f0 <5046d2880fec7d49ebed2fd2866747ee1d06ad71

Linux patch: 7.3

Linux patch: 0

Linux 4.4

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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Exploit and PoC references, threat intelligence from 22 sources

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Lifecycle Timeline

Patch available

Oct 28, 2026 - 11:02 EUVD

CVE Published

Oct 28, 2026 - 10:34 cve.org

UNKNOWN (no severity yet)

Threat Intelligence Overview

Data Quality

2 sources

Confidence: Low

EUVD

CVE.org

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity Not scored yet

CISA KEV No

Public POC No

EPSS N/A

Patch available Yes

Active threat No

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

Awaiting Data No severity or threat signals available yet. Label will update when CVSS score is published or threat intelligence arrives.

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.