CVE-2026-40496: FreeScout is a free self-hosted help desk and shared mailbox

Q: How do I fix CVE-2026-40496?

freescout: upgrade to 1.8.213. Exact commands for each OS are on this page.

Q: Is CVE-2026-40496 being exploited?

CVE-2026-40496 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-2026-40496 affect?

CVE-2026-40496 affects freescout. Severity is critical (CVSS 9.1). FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, attachment download tokens are generated using a weak and predictable formula: `md5(APP_KEY + attachment_id + size)`. Since attachment_id is sequential

Q: How urgent is CVE-2026-40496?

Priority 50/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-40496 is a critical-severity flaw (CVSS 9.1) affecting freescout. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, attachment download tokens are generated using a weak and predictable formula: `md5(APP_KEY + attachment_id + size)`. Since attachment_id is sequential and size can be brute-forced in a small range, an unauthenticated attacker can forge valid tokens and download any private attachment without credentials. Version 1.8.213 fixes the issue.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-330, CWE-340
Published	2026-04-21
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: freescout

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-21 02:16 UTCPublished CVE record published
2026-06-17 10:45 UTCUpdated Record last modified

freescout freescout UPGRADE

Affected: < 1.8.213

Fixed in: 1.8.213

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 1.8.213 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade freescout

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-2026-40496?

freescout: upgrade to 1.8.213. Exact commands for each OS are on this page.

Is CVE-2026-40496 being exploited?

CVE-2026-40496 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-2026-40496 affect?

CVE-2026-40496 affects freescout. Severity is critical (CVSS 9.1). FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, attachment download tokens are generated using a weak and predictable formula: `md5(APP_KEY + attachment_id + size)`. Since attachment_id is sequential

How urgent is CVE-2026-40496?

Priority 50/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-40565 MEDIUM 6.1 UPGRADE FreeScout is a free self-hosted help desk and shared mailbox
CVE-2026-40498 CRITICAL 9.8 UPGRADE FreeScout is a free self-hosted help desk and shared mailbox
CVE-2026-40497 HIGH 8.1 UPGRADE FreeScout is a free self-hosted help desk and shared mailbox

References

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