CVE-2006-3251

CVE-2006-3251 is a high-severity vulnerability in Hashcash with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

Description

Heap-based buffer overflow in the array_push function in hashcash.c for Hashcash before 1.21 might allow attackers to execute arbitrary code via crafted entries.

Frequently asked questions

What is CVE-2006-3251?
Heap-based buffer overflow in the array_push function in hashcash.c for Hashcash before 1.21 might allow attackers to execute arbitrary code via crafted entries.
How severe is CVE-2006-3251?
CVE-2006-3251 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2006-3251 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2006-3251?
CVE-2006-3251 primarily affects Hashcash. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2006-3251?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2006-3251 published?
CVE-2006-3251 was published on 2006-06-27 and last updated on 2026-06-16.

References

Affected products (21)

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