PatchTheCVECVE-2019-25220: Bitcoin Core before 24.0.1 allows remote attackers to cause a denial of service (daemon crash) via a flood of
CVE-2019-25220 is a high-severity flaw (CVSS 7.5) affecting bitcoin core. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Bitcoin Core before 24.0.1 allows remote attackers to cause a denial of service (daemon crash) via a flood of low-difficulty header chains (aka a "Chain Width Expansion" attack) because a node does not first verify that a presented chain has enough work before committing to store it.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.8% (top 43%) |
| CISA exploited list | No |
| Weakness | CWE-770 |
| Published | 2024-11-18 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
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-2019-25220?
bitcoin core: upgrade to 24.0.1. Exact commands for each OS are on this page.
Is CVE-2019-25220 being exploited?
CVE-2019-25220 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-2019-25220 affect?
CVE-2019-25220 affects bitcoin core. Severity is high (CVSS 7.5). Bitcoin Core before 24.0.1 allows remote attackers to cause a denial of service (daemon crash) via a flood of low-difficulty header chains (aka a "Chain Width Expansion" attack) because a node does not first verify that a presented chain ha
How urgent is CVE-2019-25220?
Priority 46/100. High severity; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2025-54605 HIGH 7.5 UPGRADE Bitcoin Core through 29.0 allows Uncontrolled Resource Consumption (issue 2 of 2).
- CVE-2025-54604 HIGH 7.5 UPGRADE Bitcoin Core through 29.0 allows Uncontrolled Resource Consumption (issue 1 of 2).
- CVE-2025-46598 MEDIUM 5.3 UPGRADE Bitcoin Core through 29.0 allows a denial of service via a crafted transaction.
- CVE-2025-46597 HIGH 7.5 UPGRADE Bitcoin Core 0.13.0 through 29.x has an integer overflow.
- CVE-2024-55563 MEDIUM 5.3 UPGRADE Bitcoin Core through 27.2 allows transaction-relay jamming via an off-chain protocol attack, a related issue t