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Fencer Vulns
medium 6.3

CVE-2026-46403 json

Klever-Go KVM read-only execution can commit contract delete and upgrade side effects

published 2026-05-21 5 mo ago modified 2026-10-24 15 d ago also GHSA-jc6w-wmfc-fh33 , GO-2026-5461 , EUVD-2026-46390

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/klever-io/klever-go 1.7.17
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/klever-io/klever-go/security/advisories/GHSA-jc6w-wmfc-fh33 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N
GitHub 3.1 6.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/klever-io/klever-go
<1.7.17
1.7.17

Affected products

  • klever-io klever-go

Classification

Weakness
  • CWE-693 Protection Mechanism Failure

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.