CVE-2021-33054: SOGo 2.x before 2.4.1 and 3.x through 5.x before 5.1.1 does not validate the signatures of any SAML assertions

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2021-33054 is a high-severity flaw (CVSS 7.5) affecting sogo, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

SOGo 2.x before 2.4.1 and 3.x through 5.x before 5.1.1 does not validate the signatures of any SAML assertions it receives. Any actor with network access to the deployment could impersonate users when SAML is the authentication method. (Only versions after 2.0.5a are affected.)

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 37%)
CISA exploited list	No
Weakness	CWE-347
Published	2021-06-04
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · inverse

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

Am I affected?

Timeline

2021-06-04 15:15 UTCPublished CVE record published
2026-06-17 03:54 UTCUpdated Record last modified

inverse sogo UPGRADE

Affected: >= 2.0.6 and < 2.4.1 · >= 3.0.0 and < 5.1.1

Fixed in: 2.4.1, 5.1.1

Safe to downgrade to: a release before 2.0.6

1. Check installed version

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

2. UPGRADE to 2.4.1 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sogo

Note

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

3. If no update is available yet, DOWNGRADE to a release before 2.0.6 (Debian / Ubuntu)

apt-cache madison sogo sudo apt install sogo=<VERSION_BEFORE_2.0.6> sudo apt-mark hold sogo

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list sogo sudo dnf downgrade sogo-<VERSION_BEFORE_2.0.6> sudo dnf versionlock add sogo

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

debian debian linux MITIGATE

Affected: 9.0 · 10.0 · 11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2021-33054?

sogo: upgrade to 2.4.1, 5.1.1; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-33054 being exploited?

CVE-2021-33054 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-2021-33054 affect?

CVE-2021-33054 affects sogo, debian linux. Severity is high (CVSS 7.5). SOGo 2.x before 2.4.1 and 3.x through 5.x before 5.1.1 does not validate the signatures of any SAML assertions it receives. Any actor with network access to the deployment could impersonate users when SAML is the authentication method. (Onl

How urgent is CVE-2021-33054?

Priority 52/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2025-63499 MEDIUM 6.1 UPGRADE Alinto Sogo 5.12.3 is vulnerable to Cross Site Scripting (XSS) via the theme parameter.
CVE-2026-3054 MEDIUM 4.3 DOWNGRADE A vulnerability was identified in Alinto SOGo 5.12.3/5.12.4
CVE-2026-33550 LOW 2.0 UPGRADE SOGo before 5.12.5 does not renew the OTP if a user disables/enables it, and has a too short length (only 12 d
CVE-2025-71276 MEDIUM 6.4 UPGRADE SOGo before 5.12.5 is prone to a XSS vulnerability with events, tasks, and contacts categories.
CVE-2025-63498 MEDIUM 6.1 DOWNGRADE MITIGATE alinto SOGo 5.12.3 is vulnerable to Cross Site Scripting (XSS) via the "userName" parameter.

References

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