CVE-2026-8670 | Insecure session handling on metrics web server

Insufficient session expiration vulnerability in syslink software AG Avantra on Linux, Windows allows Reusing Session IDs (aka Session Replay). This issue affects Avantra: before 25.3.1.

Published: 2026-05-22 Last update: 2026-06-02 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-8670 is rated Moderate Risk (42.4/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.04%). Review affected assets and schedule remediation.

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-2026-8670

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 2026-05-23 — 0.04% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-8670

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.6 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H 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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 6.0 [email protected]

Weakness enumeration for CVE-2026-8670

GitHub Security Advisory for CVE-2026-8670

GHSA-rvw7-wx4g-rq78 · Severity: critical — Insufficient session expiration vulnerability in syslink software AG Avantra on Linux, Windows...

Affected software / configurations for CVE-2026-8670

Vendor Product Version Raw CPE
avantra avantra < 25.3.1 cpe:2.3:a:avantra:avantra:*:*:*:*:*:*:*:*

References for CVE-2026-8670

cvelogic Threat Intelligence