GHSA-27vh-h6mc-q6g8 is a high-severity (CVSS 7.4) CWE-670 vulnerability in github.com/btcsuite/btcd. A fix is available for github.com/btcsuite/btcd — see the affected versions and patch details below.
btcd did not correctly re-implement Bitcoin Core's "FindAndDelete()" functionality
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-27vh-h6mc-q6g8.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-27vh-h6mc-q6g8 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/btcsuite/btcdReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The btcd Bitcoin client (versions 0.10 to 0.24) did not correctly re-implement Bitcoin Core's "FindAndDelete()" functionality. This logic is consensus-critical: the difference in behavior with the other Bitcoin clients can lead to btcd clients accepting an invalid Bitcoin block (or rejecting a valid one).
This consensus failure can be leveraged to cause a chain split (accepting an invalid Bitcoin block) or be exploited to DoS the btcd nodes (rejecting a valid Bitcoin block). An attacker can create a standard transaction where FindAndDelete doesn't return a match but removeOpCodeByData does making btcd get a different sighash, leading to a chain split. Importantly, this vulnerability can be exploited remotely by any Bitcoin user and does not require any hash power. This is because the difference in behavior can be triggered by a "standard" Bitcoin transaction, that is a transaction which gets relayed through the P2P network before it gets included in a Bitcoin block.
FindAndDelete vs. removeOpcodeByData
removeOpcodeByData(script []byte, dataToRemove []byte) removes any data pushes from script that contain dataToRemove. However, FindAndDelete only removes exact matches. So for example, with script = "<data> <data||foo>" and dataToRemove = "data" btcd will remove both data pushes but Bitcoin Core's FindAndDelete only removes the first <data> push.
Patches
This has been patched in btcd version v0.24.2-beta.
References
FindAndDelete: https://github.com/btcsuite/btcd/security/advisories/GHSA-27vh-h6mc-q6g8
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/btcsuite/btcd | all versions | 0.24.2-beta.rc1go get github.com/btcsuite/btcd@v0.24.2-beta.rc1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/btcsuite/btcd, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/btcsuite/btcd to 0.24.2-beta.rc1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-27vh-h6mc-q6g8 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-27vh-h6mc-q6g8 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-27vh-h6mc-q6g8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-27vh-h6mc-q6g8 in your dependencies?
O3 Security finds GHSA-27vh-h6mc-q6g8 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.