Cryptographic issues in circl - CVE-2025-8556
Published: November 14, 2025
Vulnerability identifier: #VU118530
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-8556
CWE-ID: CWE-310
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Cloudflare
Affected software:
circl
circl
Detailed vulnerability description
The vulnerability allows a remote attacker to compromise session security.
The vulnerability exists due to an error in FourQ elliptic curve implementation and incorrect point validation during Diffie-Hellman key exchange. A remote attacker can compromise session security via low-order point injection and gain access to sensitive information.
How to mitigate CVE-2025-8556
Install updates from vendor's website.
Sources
- https://access.redhat.com/security/cve/CVE-2025-8556
- https://bugzilla.redhat.com/show_bug.cgi?id=2371624
- https://github.com/cloudflare/circl/security/advisories/GHSA-2x5j-vhc8-9cwm
- https://github.com/cloudflare/circl/tree/v1.6.1
- https://news.ycombinator.com/item?id=45669593
- https://www.botanica.software/blog/cryptographic-issues-in-cloudflares-circl-fourq-implementation