CVE-2019-25220 — Bitcoin Core before 24

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 committin

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2024-11-18T00:00:00.000Z
• Last modified: 2024-11-18T16:28:52.209Z

09References

• en.bitcoin.it — https://en.bitcoin.it/wiki/Common_Vulnerabilities_and_Exposures
• bitcoincore.org — https://bitcoincore.org/en/2024/09/18/disclose-headers-oom
• lists.linuxfoundation.org — https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2019-October/017354.html