Evidence used
- No CISA KEV confirmation is currently recorded.
- Exploitation requires an existing local or physical foothold with privileges.
- EPSS is 0.77% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2021
CVE-2021-22716High confidence
A CWE-732: Incorrect Permission Assignment for Critical Resource vulnerability exists that could allow remote code execution when an unprivileged user modifies a file
Schneider Electric · C-Bus Toolkit
7.8HighCVSS 3.1
Within 7 days
Patch availableHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:Medium, lowered one band.downgradedsince 16 Sep 2024
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict local access and enforce least privilege on affected hosts.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Schneider Electric C-Bus Toolkit and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Direct vendor intelligence
1 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
SEVD-2021-103-01 · CSAF 2.0 · revision 3.1.0 · finalSchneider Electric CPCERTC-Bus Toolkit and C-Gate Server
The vendor explicitly identifies these products as affected by this CVE.
- Schneider Electric C-Bus Toolkit <1.15.9
- Schneider Electric C-Gate Server <2.11.7
- Summary
- A CWE-732: Incorrect Permission Assignment for Critical Resource vulnerability exists that could allow remote code execution when an unprivileged user modifies a file.
- Remediation
- Version 1.15.10 of the C-Bus Toolkit product, which contains the C-Gate Server, includes a fix for these vulnerabilities and is available for download here:
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
A CWE-732: Incorrect Permission Assignment for Critical Resource vulnerability exists that could allow remote code execution when an unprivileged user modifies a file. Affected Product: C-Bus Toolkit (V1.15.9 and prior)
What
A CWE-732: Incorrect Permission Assignment for Critical Resource vulnerability exists that could allow remote code execution when an unprivileged user modifies a file. Affected Product: C-Bus Toolkit (V1.15.9 and prior)
Why
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.
What
A CWE-732: Incorrect Permission Assignment for Critical Resource vulnerability exists that could allow remote code execution when an unprivileged user modifies a file. Affected Product: C-Bus Toolkit (V1.15.9 and prior)
Why
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- local access → Incorrect Permission Assignment for Critical Resource → execute code or commands in the affected security context
- Attack surface
- Local
- Privileges required
- Low: a basic authenticated account is required
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-732 ↗
CWE-732: Incorrect Permission Assignment for Critical Resource. The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Patch available
- Action
- Version 1.15.10 of the C-Bus Toolkit product, which contains the C-Gate Server, includes a fix for these vulnerabilities and is available for download here:
- Workaround
- No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04
Evidence and provenance
Published 13 Apr 2021 · Last source change 16 Sept 2024, 22:02 UTC · CWE-732 · Incorrect Permission Assignment for Critical Resource
CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2021-9851
Product sourceVendor CSAF · Schneider Electric CPCERT
Remediation sourceVendor CSAF · Schneider Electric CPCERT
CWE sourceCNA
NVD statusNVD modified after enrichment
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.Schneider Electric CPCERT ↗
- Before
- V < 1.15.9 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- After
- V < 1.15.9 · Fixed: Version 1.15.10 of the C-Bus Toolkit product, which contains the C-Gate Server, includes a fix for these vulnerabilities and is available for download here:
- Remediation statusRemediation status changed from Awaiting fix to Patch available.Schneider Electric CPCERT ↗
- Before
- Awaiting fix
- After
- Patch available
CVE published
Fixed release recorded from official guidance
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.