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Kiteworks Core CVE-2026-102136

| EUVDEUVD-2026-90279 MEDIUM
Improper Neutralization of CRLF Sequences ('CRLF Injection') (CWE-93)
2026-09-30 cisa-cg
6.3
CVSS 3.1 · Vendor: cisa-cg
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Gain code execution on one cluster node
  2. Delivery
    Submit crafted value via internal cluster interface
  3. Exploit
    Value injected into monitoring config on second node
  4. Execution
    OS command executes as unprivileged service account
  5. Impact
    Lateral foothold across cluster nodes

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization CRLF sequence sanitization
Exploitation Conditions

Requires a MULTI-NODE (clustered) Kiteworks Core deployment - single-node installs are not exposed via this path. The attacker must ALREADY possess code execution on one appliance node, since the vulnerable input is reachable only through the internal cluster interface, not from the public network. Exploitation writes an unvalidated value into the monitoring configuration of a second node; resulting command execution is limited to an unprivileged service account, so it does not directly yield root/privileged control on the target node. Affected versions are Kiteworks Core below 9.5.1; patched in 9.5.1.

Impact

This is a genuinely low-to-medium priority issue despite the OS-command-execution potential, because every strong exploitation signal is gated. The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L, 6.3) explicitly requires LOCAL access and LOW privileges - and the description clarifies that 'local' here means the attacker must ALREADY have code execution on one appliance node in a multi-node cluster. There is no EPSS score, no CISA KEV listing, and no public POC identified at time of analysis, so exploitation status is: no public exploit identified at time of analysis. The scope change (S:C) is the one aggravating factor - the injected value crosses from one node into the monitoring configuration of a different node - but the resulting command execution is confined to an unprivileged service account, which is why C/I/A are all Low rather than High. No SSVC decision data was supplied. Net: this is a real defense-in-depth flaw for lateral movement within a compromised cluster, not a widespread remote-exploitation priority. It should be patched but does not warrant emergency response absent evidence of an initial-access chain.

Exploit ScenarioDerived

An attacker who has already compromised one Kiteworks appliance node (via a separate initial-access vulnerability) submits a crafted value through the internal cluster interface. That value is written into the monitoring configuration on a second node without sufficient neutralization of special/CRLF elements (CWE-93), causing OS commands to run on that second node as the unprivileged service account, extending the attacker's foothold laterally across the cluster. No public POC is identified at time of analysis.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 30, 2026

OS command execution on a second appliance node is possible in multi-node (clustered) Kiteworks Core deployments running versions below 9.5.1, but only for an attacker who has already achieved code execution on another node in the same cluster. An unvalidated value submitted through an internal cluster interface is written into the monitoring configuration of a peer node, where it can be interpreted as an OS command running under an unprivileged service account. There is no public exploit identified at time of analysis and no confirmed active exploitation (CISA KEV); the CVSS 3.1 score of 6.3 (AV:L/PR:L/S:C) reflects the strong prerequisites - local-adjacent access, existing low-privilege foothold, and a multi-node topology.

RemediationAI

Vendor-released patch: Kiteworks Core 9.5.1, which remediates the missing neutralization on the internal cluster interface; upgrade all nodes in every cluster to 9.5.1 or later, since a mixed-version cluster leaves at least one peer writable by an older node. Consult GHSA-rpxx-jm93-w5j7 and CSAF VA-26-274-01 for the vendor's authoritative guidance and any release notes on cluster upgrade ordering. If an immediate upgrade is not feasible, the practical compensating controls follow directly from the exploitation prerequisites: (1) treat this as a post-compromise escalation path and prioritize detecting and containing any existing code execution on cluster nodes, since that is a hard prerequisite - trade-off is that this is detection, not prevention; (2) tightly segment and firewall the internal cluster/monitoring interface so only legitimate peer node addresses can reach it, with the trade-off that misconfigured rules can break cluster health checks and monitoring ingestion; (3) monitor and alert on unexpected changes to monitoring configuration files and unexpected child processes spawned by the monitoring service account, accepting that this detects rather than blocks exploitation; (4) run the monitoring and cluster services under the least-privileged service accounts available, which limits but does not eliminate the impact given execution is already confined to an unprivileged account. Because the CVSS vector requires AV:L and PR:L, there is no meaningful benefit to perimeter-only mitigation such as blocking public ports - the vulnerable interface is internal by design.

Affected VersionsENISA

core 0 <9.5.1

Affected Packages

euvd core fix: 9.5.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause class is CWE-93 (Improper Neutralization of CRLF Sequences), which in this context manifests as injection into a configuration file consumed by a downstream monitoring component. The vulnerable data path is the internal cluster interface used for node-to-node coordination in Kiteworks Core; a value passed across that interface is persisted into monitoring configuration on a peer node without adequate neutralization of control/line-break characters, so injected content is parsed as additional directives or commands when the monitoring service processes its configuration. Because the write occurs on a different node than the one the attacker controls, the CVSS vector carries Scope:Changed (S:C), pushing the base score above what a same-scope injection would merit. The vector AV:L/AC:L/PR:L/UI:N describes a local/adjacent attack requiring an existing low-privileged foothold and no user interaction. Execution is constrained to an unprivileged service account, so the flaw does not by itself grant root or administrative control of the second node, and the internal interface is not reachable from the public network. CPE data (cpe:2.3:a:kiteworks:core) and ENISA EUVD-2026-90279 both tie the issue to Kiteworks Core releases prior to 9.5.1. Tags classify the issue as an RCE affecting Core.

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Severity by source

Vendor (cisa-cg) PRIMARY 6.3 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L
vuln.today AI 6.3 MEDIUM

AV:L and PR:L because it needs prior code exec on a node reaching an internal cluster interface; S:C for cross-node impact; C/I/A Low as execution is confined to an unprivileged service account.

3.1 AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L

Primary rating from Vendor (cisa-cg).

CVSS VectorVendor: cisa-cg

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

Lifecycle Timeline

1
Patch available
Sep 30, 2026 - 21:04 EUVD

DescriptionCVE.org

In multi-node deployments, an attacker who had already obtained code execution on one appliance node could submit a value through an internal cluster interface that was written into monitoring configuration on another node without sufficient validation, potentially allowing OS commands to be executed there. Execution was limited to an unprivileged service account on that node.

Threat Intelligence Overview

EPSS Score
0.2%
Top 95% exploitable
Prevalence
Medium
Kiteworks is a common enterprise MFT/file-sharing appliance, not everywhere
Data Quality
6 sources
Confidence: High

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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

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