Evidence used
- No CISA KEV confirmation is currently recorded.
- The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
- EPSS is 1.40% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2021
CVE-2021-22731High confidence
n/a Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior — Weak Password Recovery Mechanism for Forgotten Password
Unknown · Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior
9.8CriticalCVSS 3.1
Within 72 hours
Patch availableCritical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityCritical→Operational priority:Critical, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Unknown Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior 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-2021-130-01 · CSAF 2.0 · revision 1.0.0 · finalSchneider Electric CPCERTModicon Managed Switch
The vendor explicitly identifies these products as affected by this CVE.
- Schneider Electric Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior
- Summary
- CWE-640: Weak Password Recovery Mechanism for Forgotten Password vulnerability exists that could cause an unauthorized password change through HTTP / HTTPS when basic user information is known by a remote attacker.
- Remediation
- Version 8.22 of the Modicon Managed Switch products includes a fix for this vulnerability and is available for download here: The upgrade procedure is detailed in the MCSESM, MCSESM-E Managed Switch User Manual Configuration available below, is also applicable for MCSESP references. It is important to note that the upgrade procedure must be applied twice with the same version to prevent rollback. User Manual Configuration: https://download.schneiderelectric.com/files?p_Doc_Ref=QGH59056 Customers should use appropriate patching methodologies when applying these patches to their systems. We strongly recommend the use of back-ups and evaluating the impact of these patches in a Test and Development environment or on an offline infrastructure. Contact Schneider Electric's Customer Care Center if you need assistance removing a patch.
Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.
Patch available01
What, why and how
Weak Password Recovery Mechanism for Forgotten Password vulnerability exists on Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior which could cause an unauthorized password change through HTTP / HTTPS when basic user information is known by a remote attacker.
What
Weak Password Recovery Mechanism for Forgotten Password vulnerability exists on Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior which could cause an unauthorized password change through HTTP / HTTPS when basic user information is known by a remote attacker.
Why
The product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
Weak Password Recovery Mechanism for Forgotten Password vulnerability exists on Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior which could cause an unauthorized password change through HTTP / HTTPS when basic user information is known by a remote attacker.
Why
The product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
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
- a network path → Weak Password Recovery Mechanism for Forgotten Password → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- 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-640 ↗
CWE-640: Weak Password Recovery Mechanism for Forgotten Password. The product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing 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
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
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 8.22 of the Modicon Managed Switch products includes a fix for this vulnerability and is available for download here: The upgrade procedure is detailed in the MCSESM, MCSESM-E Managed Switch User Manual Configuration available below, is also applicable for MCSESP references. It is important to note that the upgrade procedure must be applied twice with the same version to prevent rollback. User Manual Configuration: https://download.schneiderelectric.com/files?p_Doc_Ref=QGH59056 Customers should use appropriate patching methodologies when applying these patches to their systems. We strongly recommend the use of back-ups and evaluating the impact of these patches in a Test and Development environment or on an offline infrastructure. Contact Schneider Electric's Customer Care Center if you need assistance removing a patch.
- Workaround
- No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 26 May 2021 · Last source change 3 Aug 2024, 18:51 UTC · CWE-640 · Weak Password Recovery Mechanism for Forgotten Password
CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
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-2021-9866
Product sourceVendor CSAF · Schneider Electric CPCERT
Remediation sourceVendor CSAF · Schneider Electric CPCERT
CWE sourceCNA
NVD statusNVD modified after enrichment
Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.Schneider Electric CPCERT ↗
- Before
- Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
- After
- Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior · Fixed: Version 8.22 of the Modicon Managed Switch products includes a fix for this vulnerability and is available for download here: The upgrade procedure is detailed in the MCSESM, MCSESM-E Managed Switch User Manual Configuration available below, is also applicable for MCSESP references. It is important to note that the upgrade procedure must be applied twice with the same version to prevent rollback. User Manual Configuration: https://download.schneiderelectric.com/files?p_Doc_Ref=QGH59056 Customers should use appropriate patching methodologies when applying these patches to their systems. We strongly recommend the use of back-ups and evaluating the impact of these patches in a Test and Development environment or on an offline infrastructure. Contact Schneider Electric's Customer Care Center if you need assistance removing a patch.
CVE published
Fixed release or patch reference recorded
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.