Librest: weak random number generation in pkce implementation
Summary
| CVE | CVE-2026-16615 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-22 17:16:55 UTC |
| Updated | 2026-07-22 20:33:11 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 6.8 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Problem Types: CWE-338 | CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N |
| 3.1 | CNA | CVSS | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
RequiredScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| gitlab.gnome.org/GNOME/librest/-/issues/25 | [email protected] | gitlab.gnome.org | |
| access.redhat.com/security/cve/CVE-2026-16615 | [email protected] | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Cole Blakley for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-07-21T16:36:28.886Z | Reported to Red Hat. |
| CNA | 2026-02-28T00:00:00.000Z | Made public. |
Workarounds
CNA: Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.
There are currently no legacy QID mappings associated with this CVE.