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Full vulnerability report · 2026
CVE-2026-85649High confidence

chewkeanho software-actualizer: Not Failing Securely ('Failing Open')

chewkeanho · software-actualizer

7.9HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Medium, lowered one band.downgradedsince 4 Sep 2026

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.20% for the current model date.

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

  1. Confirm that the asset runs chewkeanho software-actualizer and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-71096

No EUVD known-exploited evidence

(Holloway) Chew, Kean Ho's Actualizer v1.2.0 and earlier contains a fail-open password validation vulnerability in the Alpha user and root user password loops of Shell/debian-minbase-install.sh. The installer invokes mkpasswd to generate yescrypt password hashes but does not check the command's return value and unconditionally accepts the result. If mkpasswd fails to generate a yescrypt hash, for example because an incompatible mkpasswd implementation or an environment without yescrypt support is used, the resulting password hash variable can be empty and the build proceeds. The resulting image can therefore contain empty password fields for the root and alpha accounts, potentially permitting passwordless authentication depending on the authentication configuration.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
7.9 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

(Holloway) Chew, Kean Ho's Actualizer v1.2.0 and earlier contains a fail-open password validation vulnerability in the Alpha user and root user password loops of Shell/debian-minbase-install.sh. The installer invokes mkpasswd to generate yescrypt password hashes but does not check the command's return value and unconditionally accepts the result. If mkpasswd fails to generate a yescrypt hash, for example because an incompatible mkpasswd implementation or an environment without yescrypt support is used, the resulting password hash variable can be empty and the build proceeds. The resulting image can therefore contain empty password fields for the root and alpha accounts, potentially permitting passwordless authentication depending on the authentication configuration.

What

(Holloway) Chew, Kean Ho's Actualizer v1.2.0 and earlier contains a fail-open password validation vulnerability in the Alpha user and root user password loops of Shell/debian-minbase-install.sh. The installer invokes mkpasswd to generate yescrypt password hashes but does not check the command's return value and unconditionally accepts the result. If mkpasswd fails to generate a yescrypt hash, for example because an incompatible mkpasswd implementation or an environment without yescrypt support is used, the resulting password hash variable can be empty and the build proceeds. The resulting image can therefore contain empty password fields for the root and alpha accounts, potentially permitting passwordless authentication depending on the authentication configuration.

Why

When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

(Holloway) Chew, Kean Ho's Actualizer v1.2.0 and earlier contains a fail-open password validation vulnerability in the Alpha user and root user password loops of Shell/debian-minbase-install.sh. The installer invokes mkpasswd to generate yescrypt password hashes but does not check the command's return value and unconditionally accepts the result. If mkpasswd fails to generate a yescrypt hash, for example because an incompatible mkpasswd implementation or an environment without yescrypt support is used, the resulting password hash variable can be empty and the build proceeds. The resulting image can therefore contain empty password fields for the root and alpha accounts, potentially permitting passwordless authentication depending on the authentication configuration.

Why

When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.

How

An attacker operating through local access may attempt exploitation with elevated privileges. 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
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

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
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

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 → Not Failing Securely ('Failing Open') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
High: elevated access is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-636 ↗

CWE-636: Not Failing Securely ('Failing Open'). When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.

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:H/UI:N/S:C/C:H/I:H/A:N

Common 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.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
CWE-636
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-71096Official EUVD mapping

(Holloway) Chew, Kean Ho's Actualizer v1.2.0 and earlier contains a fail-open password validation vulnerability in the Alpha user and root user password loops of Shell/debian-minbase-install.sh. The installer invokes mkpasswd to generate yescrypt password hashes but does not check the command's return value and unconditionally accepts the result. If mkpasswd fails to generate a yescrypt hash, for example because an incompatible mkpasswd implementation or an environment without yescrypt support is used, the resulting password hash variable can be empty and the build proceeds. The resulting image can therefore contain empty password fields for the root and alpha accounts, potentially permitting passwordless authentication depending on the authentication configuration.

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260909Security Bulletin 9 Sep 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 9 Sep 2026, published on 9 September 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
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
Affected
software-actualizer: ≤ 1.2.0
Fixed
Upgrade to Actualizer v1.2.1 or later. The fixed version validates that the generated password hash has the expected yescrypt prefix and performs a pre-flight check for yescrypt support before building.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 4 Sept 2026 · Last source change 4 Sept 2026, 17:59 UTC · CWE-636 · Not Failing Securely ('Failing Open')

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-05
European sourceENISA EUVD · EUVD-2026-71096
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD awaiting enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA EUVD mappingEUVD-2026-71096 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-71096"}
    ENISA EUVD ↗
  2. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-71096↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
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.
Free version - for non-commercial use only.CVE-2026-85649 · cve.blacktree.nl