Red Hat librest 2.0 PKCE GRand random values

Summaryinfo

A vulnerability has been found in Red Hat librest 2.0 and classified as problematic. This vulnerability affects the function GRand of the component PKCE. The manipulation leads to random values. This vulnerability is referenced as CVE-2026-16615. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Red Hat librest 2.0. This issue affects the function GRand of the component PKCE. The manipulation with an unknown input leads to a random values vulnerability. Using CWE to declare the problem leads to CWE-330. The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers. Impacted is confidentiality. The summary by CVE is:

A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.

The advisory is shared at access.redhat.com. The identification of this vulnerability is CVE-2026-16615 since 07/22/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/22/2026). MITRE ATT&CK project uses the attack technique T1600.001 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• Red Hat

Name

• librest

Version

• 2.0

License

• open-source

Website

• Vendor: https://www.redhat.com/

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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