CVE-2026-53658 Fabric CA: LDAP Injection via Unescaped Username in GetUser Filter
An unauthenticated attacker can inject LDAP metacharacters into the username field to bypass authentication checks in Hyperledger Fabric CA when using an LDAP backend.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53658?
CVE-2026-53658 is a medium-severity vulnerability in hyperledger fabric-ca, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Fabric CA is a Certificate Authority for Hyperledger Fabric. Prior to 1.5.21, when fabric-ca is configured with an LDAP backend, Client.GetUser in lib/server/ldap/client.go inserts the username from HTTP Basic authentication into the LDAP uid search UserFilter without escaping LDAP metacharacters. An unauthenticated attacker with network access to the CA enrollment endpoint can alter the LDAP search before password validation and potentially steer authentication attempts toward a victim account. Deployments that do not use an LDAP backend are unaffected. This issue is fixed in version 1.5.21.
Weakness: CWE-90
Which versions are affected by CVE-2026-53658?
3 open source packages ship an affected version, including github.com/hyperledger/fabric-ca.
| Package | Affected | Fixed in |
|---|---|---|
github.com/hyperledger/fabric-ca Go | All versions | 1.5.21 |
github.com/hyperledger/fabric-ca Go | All versions | 1.5.21 |
github.com/hyperledger/fabric-ca Go | All versions | 1.5.21 |
How do I fix CVE-2026-53658?
Upgrade github.com/hyperledger/fabric-ca to 1.5.21 or later.
Is CVE-2026-53658 being exploited?
There is no known exploitation of CVE-2026-53658 in the wild and no public exploit code.
Sources
Also known as GHSA-xghw-p77p-3r7x, GO-2026-6234.