CVE-2026-8670: Insufficient session expiration vulnerability in syslink software AG Avantra on Linux, Windows allows Reusing

Q: How do I fix CVE-2026-8670?

avantra: upgrade to 25.3.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-8670 being exploited?

CVE-2026-8670 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-8670 affect?

CVE-2026-8670 affects avantra. Severity is critical (CVSS 9.6). 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.

Q: How urgent is CVE-2026-8670?

Priority 42/100. Critical severity; On your watchlist

This month

CRITICAL 9.6WATCHLISTUPGRADE

CVE-2026-8670 is a critical-severity flaw (CVSS 9.6) affecting avantra. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.6 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-613
Published	2026-05-22
Last modified	2026-07-23

Publisher (CNA): Switzerland Government Common Vulnerability Program · Vendor: avantra

Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-22 14:16 UTCPublished CVE record published
2026-07-23 16:10 UTCUpdated Record last modified

avantra avantra UPGRADE

Affected: < 25.3.1

Fixed in: 25.3.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy avantra || rpm -q avantra || avantra --version

2. UPGRADE to 25.3.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade avantra

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade avantra

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-8670?

avantra: upgrade to 25.3.1. Exact commands for each OS are on this page.

Is CVE-2026-8670 being exploited?

CVE-2026-8670 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-8670 affect?

CVE-2026-8670 affects avantra. Severity is critical (CVSS 9.6). 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.

How urgent is CVE-2026-8670?

Priority 42/100. Critical severity; On your watchlist

Software pages

Windows vulnerabilities

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References

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