CVE-2026-63761 SurrealDB before 3.1.0 Algorithm Downgrade via ES512

Medium 5.3 Published Updated

SurrealDB silently downgrades JWT ES512 to ES384, causing authentication failures and potential security bypasses in specific configurations.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2026-63761?

CVE-2026-63761 is a medium-severity vulnerability in Surrealdb Surrealdb, published on 20 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

SurrealDB before 3.1.0 silently substitutes the ES384 algorithm when a JWT access method is configured with ALGORITHM ES512 (DEFINE ACCESS ... TYPE JWT ALGORITHM ES512), because the underlying jsonwebtoken crate (v10.x) has no ES512 variant and the mapping defaults to ES384 without any error, warning, or log message. Users who supply the correct P-521 key for ES512 experience authentication handshake failures due to the curve mismatch with ES384 (which expects P-384), and tokens are rejected by external systems expecting genuine ES512 signatures. The flaw cannot be used to forge tokens or compromise data confidentiality or integrity, as ES384 remains cryptographically strong.

Weakness: CWE-327

Which versions are affected by CVE-2026-63761?

2 open source packages ship an affected version, including surrealdb. It affects 1 product.

PackageAffectedFixed in
surrealdb crates.ioAll versions3.1.0
surrealdb crates.ioAll versions3.1.0

Products include Surrealdb Surrealdb.

How do I fix CVE-2026-63761?

Upgrade surrealdb to 3.1.0 or later.

Is CVE-2026-63761 being exploited?

There is no known exploitation of CVE-2026-63761 in the wild and no public exploit code.

All Surrealdb Surrealdb vulnerabilities

Sources

Also known as GHSA-fwg2-gr34-q3w8.

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