GHSA-27vh-h6mc-q6g8 is a high-severity (CVSS 7.4) CWE-670 vulnerability in github.com/btcsuite/btcd. O3 Security confirms whether GHSA-27vh-h6mc-q6g8 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
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.
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.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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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 pinpoints whether GHSA-27vh-h6mc-q6g8 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
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 detects GHSA-27vh-h6mc-q6g8 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.