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.
CVE-2026-16615
MEDIUMPre-NVD 6.86.8—Trending — 3 sources updated this week
EchelonGraph scoreHIGH confidence
Score 6.8 from GitHub Security Advisory published 2026-07-22. a secondary CVSS source baseline 6.8; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
6.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: —CVSS: 6.8Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.8
- EG Score
- 6.8(high)
- EG Risk
- —
- EPSS
- —
- KEV
- Not listed
Published
July 22, 2026
Last Modified
July 22, 2026
Advisory Details (3)
Auto-updated Jul 22, 2026Patch available. Sources: redhat.
generic
Weak random number generation in PKCE implementation (#25) · Issues · GNOME / librest · GitLab
https://gitlab.gnome.org/GNOME/librest/-/issues/25redhat
2504432 – (CVE-2026-16615) CVE-2026-16615 librest: weak random number generation in PKCE implementation
https://bugzilla.redhat.com/show_bug.cgi?id=2504432Vendor Advisories for CVE-2026-16615(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-22 21:58 UTCEG score recompute
- 2026-07-22 21:58 UTCGHSA enrichment
- 2026-07-22 18:34 UTCEG score recompute
- 2026-07-22 18:33 UTCGHSA enrichment
- 2026-07-22 16:31 UTCEG score recompute
- 2026-07-22 16:30 UTCMITRE cvelistV5first tracked
Frequently asked(4)
What is CVE-2026-16615?
CVE-2026-16615 is a medium vulnerability published on July 22, 2026. 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…
When was CVE-2026-16615 disclosed?
CVE-2026-16615 was first published in the National Vulnerability Database on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-16615?
CVE-2026-16615 has a CVSS v3 base score of 6.8 (NVD).
How do I remediate CVE-2026-16615?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16615, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-16615
Is Your Infrastructure Affected by CVE-2026-16615?
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