CVE-2021-3740: A Session Fixation vulnerability exists in chatwoot/chatwoot versions prior to 2.4.0

Q: How do I fix CVE-2021-3740?

chatwoot: upgrade to 2.4.0. Exact commands for each OS are on this page.

Q: Is CVE-2021-3740 being exploited?

CVE-2021-3740 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-2021-3740 affect?

CVE-2021-3740 affects chatwoot. Severity is medium (CVSS 6.8). A Session Fixation vulnerability exists in chatwoot/chatwoot versions prior to 2.4.0. The application does not invalidate existing sessions on other devices when a user changes their password, allowing old sessions to persist. This can lead

Q: How urgent is CVE-2021-3740?

Priority 27/100. No elevated risk signals yet.

Routine

MEDIUM 6.8UPGRADE

CVE-2021-3740 is a medium-severity flaw (CVSS 6.8) affecting chatwoot. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A Session Fixation vulnerability exists in chatwoot/chatwoot versions prior to 2.4.0. The application does not invalidate existing sessions on other devices when a user changes their password, allowing old sessions to persist. This can lead to unauthorized access if an attacker has obtained a session token.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.8 (Medium)
Attack vector	Adjacent network
Attack complexity	High
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 89%)
CISA exploited list	No
Weakness	CWE-384
Published	2024-11-15
Last modified	2026-06-17

Publisher (CNA): huntr.dev · Vendor: chatwoot

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

Am I affected?

Timeline

2024-11-15 11:15 UTCPublished CVE record published
2026-06-17 04:05 UTCUpdated Record last modified

chatwoot chatwoot UPGRADE

Affected: < 2.4.0

Fixed in: 2.4.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 2.4.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade chatwoot

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-2021-3740?

chatwoot: upgrade to 2.4.0. Exact commands for each OS are on this page.

Is CVE-2021-3740 being exploited?

CVE-2021-3740 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-2021-3740 affect?

CVE-2021-3740 affects chatwoot. Severity is medium (CVSS 6.8). A Session Fixation vulnerability exists in chatwoot/chatwoot versions prior to 2.4.0. The application does not invalidate existing sessions on other devices when a user changes their password, allowing old sessions to persist. This can lead

How urgent is CVE-2021-3740?

Priority 27/100. No elevated risk signals yet.

Related CVEs

CVE-2025-12245 MEDIUM 5.3 UPGRADE A vulnerability was identified in chatwoot up to 4.7.0
CVE-2025-12246 MEDIUM 4.3 UPGRADE A security flaw has been discovered in chatwoot up to 4.7.0
CVE-2025-21628 CRITICAL 9.1 UPGRADE Chatwoot is a customer engagement suite
CVE-2024-0640 MEDIUM 4.8 UPGRADE A stored cross-site scripting (XSS) vulnerability exists in chatwoot/chatwoot versions 3.0.0 to 3.5.1
CVE-2021-3742 HIGH 8.8 UPGRADE A Server-Side Request Forgery (SSRF) vulnerability was discovered in chatwoot/chatwoot, affecting all versions

References

← Back to latest CVEs