CVE-2018-12703: The approveAndCallcode function of a smart contract implementation for Block 18 (18T), an tradable Ethereum ER

This week

HIGH 7.5REMOTEMITIGATE

CVE-2018-12703 is a high-severity flaw (CVSS 7.5) affecting block18. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The approveAndCallcode function of a smart contract implementation for Block 18 (18T), an tradable Ethereum ERC20 token, allows attackers to steal assets (e.g., transfer the contract's balances into their account) because the callcode (i.e., _spender.call(_extraData)) is not verified, aka the "evilReflex" issue. NOTE: a PeckShield disclosure states "some researchers have independently discussed the mechanism of such vulnerability."

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 35%)
CISA exploited list	No
Weakness	CWE-20
Published	2018-06-25
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: block18

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-06-25 10:29 UTCPublished CVE record published
2026-06-17 01:38 UTCUpdated Record last modified

block18 block18 MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy block18 || rpm -q block18 || block18 --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-12703?

block18: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-12703 being exploited?

CVE-2018-12703 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-12703 affect?

CVE-2018-12703 affects block18. Severity is high (CVSS 7.5). The approveAndCallcode function of a smart contract implementation for Block 18 (18T), an tradable Ethereum ERC20 token, allows attackers to steal assets (e.g., transfer the contract's balances into their account) because the callcode (i.e.

How urgent is CVE-2018-12703?

Priority 53/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

← Back to latest CVEs