Evidence used
- No CISA KEV confirmation is currently recorded.
- A structured source references public exploit or proof-of-concept material.
- EPSS is 0.45% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-46403High confidence
Klever-Go KVM read-only execution can commit contract delete and upgrade side effects
klever-io · klever-go
Official source article: GitHub GHSA-JC6W-WMFC-FH33 ↗. Check the applicable product and release in the original source.
6.3MediumCVSS 3.1
Within 7 days
Fix not verifiedMedium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:High, raised one band.upgradedsince 22 Jul 2026
Compensating controls
- Restrict the affected network interface to trusted sources where business-safe.
- Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
- Confirm that the asset runs klever-io klever-go 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.
Open-source package ranges1 source-attributed range
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
| Ecosystem and package | Affected range | First fixed version | Evidence |
|---|---|---|---|
| gogithub.com/klever-io/klever-go | < 1.7.17 | 1.7.17 | GitHub advisory ↗upstream repository advisory · 21 May 2026 |
Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Fix not verified01
What, why and how
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.17, KVM exposes `ExecuteReadOnlyWithTypedArguments` as a read-only execution mechanism. The hook saves the previous read-only state, sets `runtime.SetReadOnly(true)`, executes the destination context, and then restores the previous read-only state. However, the indirect contract delete and upgrade paths do not reject execution when `runtime.ReadOnly()` is true. As a result, a contract reached through read-only execution can call the production delete hook for a target contract it owns. The delete path appends the target address to `vmOutput.DeletedAccounts`, the output context merges `DeletedAccounts` into the caller output, and the smart contract processor later processes the VM output by deleting accounts listed in that field. The root cause is that read-only mode is applied as runtime state, but not enforced by the state-changing delete and upgrade host-core paths. This breaks the expected isolation boundary for workflows that rely on read-only calls to inspect another contract without allowing that callee to produce state-changing VM output. The issue is fixed in v1.7.17. Contract delete and upgrade host-core paths now reject execution when `runtime.ReadOnly()` is true. The invariant is regression-tested for delete, upgrade, storage writes, value transfers, and any VM output field that can later mutate chain state.
What
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.17, KVM exposes `ExecuteReadOnlyWithTypedArguments` as a read-only execution mechanism. The hook saves the previous read-only state, sets `runtime.SetReadOnly(true)`, executes the destination context, and then restores the previous read-only state. However, the indirect contract delete and upgrade paths do not reject execution when `runtime.ReadOnly()` is true. As a result, a contract reached through read-only execution can call the production delete hook for a target contract it owns. The delete path appends the target address to `vmOutput.DeletedAccounts`, the output context merges `DeletedAccounts` into the caller output, and the smart contract processor later processes the VM output by deleting accounts listed in that field. The root cause is that read-only mode is applied as runtime state, but not enforced by the state-changing delete and upgrade host-core paths. This breaks the expected isolation boundary for workflows that rely on read-only calls to inspect another contract without allowing that callee to produce state-changing VM output. The issue is fixed in v1.7.17. Contract delete and upgrade host-core paths now reject execution when `runtime.ReadOnly()` is true. The invariant is regression-tested for delete, upgrade, storage writes, value transfers, and any VM output field that can later mutate chain state.
Why
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.17, KVM exposes `ExecuteReadOnlyWithTypedArguments` as a read-only execution mechanism. The hook saves the previous read-only state, sets `runtime.SetReadOnly(true)`, executes the destination context, and then restores the previous read-only state. However, the indirect contract delete and upgrade paths do not reject execution when `runtime.ReadOnly()` is true. As a result, a contract reached through read-only execution can call the production delete hook for a target contract it owns. The delete path appends the target address to `vmOutput.DeletedAccounts`, the output context merges `DeletedAccounts` into the caller output, and the smart contract processor later processes the VM output by deleting accounts listed in that field. The root cause is that read-only mode is applied as runtime state, but not enforced by the state-changing delete and upgrade host-core paths. This breaks the expected isolation boundary for workflows that rely on read-only calls to inspect another contract without allowing that callee to produce state-changing VM output. The issue is fixed in v1.7.17. Contract delete and upgrade host-core paths now reject execution when `runtime.ReadOnly()` is true. The invariant is regression-tested for delete, upgrade, storage writes, value transfers, and any VM output field that can later mutate chain state.
Why
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.
How
An attacker operating through a network path may attempt exploitation with low 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 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 Reference recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.CISA Vulnrichment records proof-of-concept exploitation in its SSVC data. BlackTree has not independently executed or validated exploit material.
- Likely attack path
- a network path → Protection Mechanism Failure → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Network
- Privileges required
- Low: a basic authenticated account is required
- User interaction
- None
- Attack complexity
- High: exploitation depends on specific conditions
- Security boundary
- Changed: exploitation can affect a different security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-693 ↗
CWE-693: Protection Mechanism Failure. The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.
- 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:H/PR:L/UI:N/S:C/C:N/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.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.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
- 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. - Fix not verified
- Affected
- klever-go: < 1.7.17
- 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 21 Jul 2026 · Last source change 22 Jul 2026, 14:28 UTC · CWE-693 · Protection Mechanism Failure
CVE recordCVE.org · 5.2
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-2026-46390
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
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.