CVE-2025-8556 | Github.com/cloudflare/circl: circl-fourq: missing and wrong validation can lead to incorrect results

A flaw was found in CIRCL's implementation of the FourQ elliptic curve. This vulnerability allows an attacker to compromise session security via low-order point injection and incorrect point validation during Diffie-Hellman key exchange.

Published: 2025-08-06 Last update: 2026-04-15 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-8556 is rated Low Risk (23.8/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.09%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-8556

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-02 0.03% 0.09% +0.06%
2 2025-08-06 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-8556

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.7 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 1.4 [email protected]

Weakness enumeration for CVE-2025-8556

GitHub Security Advisory for CVE-2025-8556

GHSA-2x5j-vhc8-9cwm · Severity: low · Ecosystem: go — CIRCL-Fourq: Missing and wrong validation can lead to incorrect results

OS Trackers for CVE-2025-8556

vendor priority summary link
debian not yet assigned CVE-2025-8556 not yet assigned priority: Debian including 1 source packages (golang-github-cloudflare-circl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2025-8556
redhat low — https://access.redhat.com/security/cve/CVE-2025-8556
ubuntu medium CVE-2025-8556 medium priority: Ubuntu including 1 source packages (golang-github-cloudflare-circl), 5 status rows across 5 suites (jammy, noble, plucky, questing, upstream): needs-triage 2, ignored 1, not-affected 1, released 1. https://ubuntu.com/security/CVE-2025-8556

Affected software / configurations for CVE-2025-8556

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-8556

cvelogic Threat Intelligence