GHSA-8c37-7qx3-4c4p
Blst has logical error in SigValidate in Go bindings
Blast Radius
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Description
Impact
Blst versions v0.3.0 through 0.3.10 failed to perform a signature group-check if the call to SigValidate in the Go bindings was complemented with a check for infinity. Formally speaking, infinity, or the identity element of the elliptic curve group, is a member of the group, and the group-check should allow it. An initial review of blst users on GitHub did not uncover any use of this function with the complementary infinity check. This optional check was added as a convenience feature because despite infinity being a legitimate member of the group, individual signatures should never be infinite (as it is equivalent to having zero for the secret key), and observing one should raise a flag.
Description
The vulnerable function is declared as SigValidate(sigInfcheck bool) bool and if called with sigInfcheck argument set to true, the group-check was omitted. The group-check is required to be performed on untrusted input, because the pairing, the corner-stone operation of the signature scheme, is defined only on points that are members of a specific cyclic group, which is a subset of all the possible points on elliptic curves in question. Submitting an untrusted point outside the group opens up the possibility of accepting an alternative signature for a chosen message.
It should be noted that the SigValidate call is not the only way to perform the group-checks. There are optional checks integrated into various other verification methods, such as Verify, AggregateVerify, etc., as well as signature aggregation methods, such as PairingAggregate*. The reason why there are multiple options is that the group-check is a relatively expensive operation, and application developers are arguably entitled the freedom to choose when it's performed.
Patches
This issue has been resolved in the v0.3.11 release and users are advised to update if their application is affected or alternatively omit the complementary infinity check.
Credits
A special thanks to Yunjong Jeong (@blukat29) for the discovery and disclosure of this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/supranational/blst | ≥ 0.3.0&&< 0.3.11 | 0.3.11 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/supranational/blst. 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/supranational/blst to 0.3.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8c37-7qx3-4c4p 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-8c37-7qx3-4c4p 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-8c37-7qx3-4c4p. 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-8c37-7qx3-4c4p in your dependencies?
O3 detects GHSA-8c37-7qx3-4c4p across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.