Vulnerability in GNOME Librest
CVE-2026-16615
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (16.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- GNOME Librest — versions 0
- Red Hat Enterprise Linux 10 — versions 0:0.9.1-11.el10_2.1
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-16615 (vdb-entry)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking)
- gitlab.gnome.org/GNOME/librest/-/issues/25
- access.redhat.com/errata/RHSA-2026:47085 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:62222 (vendor-advisory)
Frequently asked questions
- What is CVE-2026-16615?
- CVE-2026-16615 is a medium-severity vulnerability in GNOME Librest, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 6.8/10. Published 2026-07-22.
- How severe is CVE-2026-16615?
- Medium severity. CVSS v3 base score is 6.8 out of 10.