Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.30% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-55610High confidence
InvoiceShelf has cross-company user read/update IDOR that enables cross-tenant account takeover
InvoiceShelf · InvoiceShelf
Official source article: GitHub GHSA-VGX6-6CQR-M8QR ↗. Check the applicable product and release in the original source.
8.7HighCVSS 3.1
Within 7 days
Fix not verifiedHigh 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:High, unchanged from published severity.unchanged
Compensating controls
- 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 InvoiceShelf InvoiceShelf and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Fix not verified01
What, why and how
InvoiceShelf is an open-source web & mobile app that helps track expenses, payments and create professional invoices and estimates. Prior to version 2.4.1, in InvoiceShelf's multi-company installations, any user who is an Owner of one company can read and overwrite any user account in any other company on the same installation. `GET/PUT /api/v1/users/{user}` resolves the target `User` by global primary key, and `UserPolicy` checks only that the requester owns their own header-company — it never verifies that the target user belongs to that company. This allows cross-tenant disclosure of user data and full account takeover (email/password overwrite + company re-assignment). Version 2.4.1 fixes the issue.
What
InvoiceShelf is an open-source web & mobile app that helps track expenses, payments and create professional invoices and estimates. Prior to version 2.4.1, in InvoiceShelf's multi-company installations, any user who is an Owner of one company can read and overwrite any user account in any other company on the same installation. `GET/PUT /api/v1/users/{user}` resolves the target `User` by global primary key, and `UserPolicy` checks only that the requester owns their own header-company — it never verifies that the target user belongs to that company. This allows cross-tenant disclosure of user data and full account takeover (email/password overwrite + company re-assignment). Version 2.4.1 fixes the issue.
Why
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
How
An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may bypass an access boundary or take over an account.
What
InvoiceShelf is an open-source web & mobile app that helps track expenses, payments and create professional invoices and estimates. Prior to version 2.4.1, in InvoiceShelf's multi-company installations, any user who is an Owner of one company can read and overwrite any user account in any other company on the same installation. `GET/PUT /api/v1/users/{user}` resolves the target `User` by global primary key, and `UserPolicy` checks only that the requester owns their own header-company — it never verifies that the target user belongs to that company. This allows cross-tenant disclosure of user data and full account takeover (email/password overwrite + company re-assignment). Version 2.4.1 fixes the issue.
Why
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
How
An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may bypass an access boundary or take over an account.
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 → Authorization Bypass Through User-Controlled Key → bypass an access boundary or take over an account
- Attack surface
- Network
- 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-639 ↗
CWE-639: Authorization Bypass Through User-Controlled Key. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
- 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:H/UI:N/S:C/C:H/I:H/A:NCommon 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.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
- Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
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. - Fix not verified
- Affected
- InvoiceShelf: < 2.4.1
- Fixed
- No fixed version is explicitly recorded in the structured CVE data.
- Action
- No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
- 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 23 Sept 2026 · Last source change 23 Sept 2026, 19:44 UTC · CWE-639 · Authorization Bypass Through User-Controlled Key
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-09-24
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-85338
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
View recent updates ↗What changed after publication
- ENISA EUVD mappingEUVD-2026-85338 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-85338"}
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
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.