How severe is CVE-2021-44549?

CVE-2021-44549 has a CVSS score of 7.4/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-44549?

CVE-2021-44549 affects the following packages: org.apache.sling:org.apache.sling.commons.messaging.mail (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-44549?

Update org.apache.sling:org.apache.sling.commons.messaging.mail to 2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-44549 is resolved across your whole dependency graph.

How do I detect CVE-2021-44549 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.sling:org.apache.sling.commons.messaging.mail, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-44549 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2021-44549 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-44549 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-44549?

CVE-2021-44549 has an EPSS (Exploit Prediction Scoring System) score of 2.1%, placing it in the 81th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-44549?

CVE-2021-44549 is classified as CWE-295 (CWE-295). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-44549 published, and has it been updated?

CVE-2021-44549 was published on December 14, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

HIGH severity

CVE-2021-44549 — org.apache.sling.commons.…

HIGH

CVE-2021-44549 is a high-severity (CVSS 7.4) CWE-295 vulnerability in org.apache.sling:org.apache.sling.commons.messaging.mail. A fix is available for org.apache.sling:org.apache.sling.commons.messaging.mail — see the affected versions and patch details below.

Improper Certificate Validation and Improper Validation of Certificate with Host Mismatch in Apache Sling Commons Messaging Mail

Also known asGHSA-c69w-jj56-834w

Published

Dec 14, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

2.1%probability of exploitation in next 30 days

Lower Risk+0.14%

Lower risk than most CVEs81th percentile — riskier than 81% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-44549 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

☕org.apache.sling:org.apache.sling.commons.messaging.mail

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Apache Sling Commons Messaging Mail provides a simple layer on top of JavaMail/Jakarta Mail for OSGi to send mails via SMTPS. To reduce the risk of "man in the middle" attacks additional server identity checks must be performed when accessing mail servers. For compatibility reasons these additional checks are disabled by default in JavaMail/Jakarta Mail. The SimpleMailService in Apache Sling Commons Messaging Mail 1.0 lacks an option to enable these checks for the shared mail session. A user could enable these checks nevertheless by accessing the session via the message created by SimpleMessageBuilder and setting the property mail.smtps.ssl.checkserveridentity to true. Apache Sling Commons Messaging Mail 2.0 adds support for enabling server identity checks and these checks are enabled by default. - https://javaee.github.io/javamail/docs/SSLNOTES.txt - https://javaee.github.io/javamail/docs/api/com/sun/mail/smtp/package-summary.html - https://github.com/eclipse-ee4j/mail/issues/429

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.sling:org.apache.sling.commons.messaging.mail`	all versions	2.0`org.apache.sling:org.apache.sling.commons.messaging.mail:2.0`

Affected Products

1 product · 1 configurations

Application

sling commons messaging mailapache

1 version

1.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.sling:org.apache.sling.commons.messaging.mail, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.sling:org.apache.sling.commons.messaging.mail to 2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-44549 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This vulnerability should be considered of important severity rather than moderate because it directly impacts the integrity and confidentiality of email communications over SMTPS. By disabling server identity checks, it leaves the communication channel vulnerable to "man-in-the-middle" (MITM) attacks, where an…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Source: Red Hat security advisory for CVE-2021-44549 (CC BY 4.0)

Product	Fixed in	Advisory
OCP-Tools-4.12-RHEL-8	`jenkins-0:2.462.3.1730119132-3.el8`	RHSA-2024:8886
OCP-Tools-4.13-RHEL-8	`jenkins-0:2.462.3.1729839924-3.el8`	RHSA-2024:8887
OCP-Tools-4.14-RHEL-8	`jenkins-0:2.462.3.1729839727-3.el8`	RHSA-2024:8885
OCP-Tools-4.15-RHEL-8	`jenkins-0:2.462.3.1729837947-3.el8`	RHSA-2024:8884
Red Hat build of Quarkus 3.2	`angus-mail`	RHSA-2024:7676
Red Hat build of Quarkus 3.8	see advisory	RHSA-2024:7670

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-44549 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

7.4/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CWE Classification

CWE-295CWE-295

Weaponization

No known public exploit tooling found.

OpenSSF Scorecard

Package health score

mail

4.7/10

Maintained10/10

Code-Review5/10

Branch-Protection0/10

Assessed Oct 12, 2026

Timeline

Disclosed

Dec 14, 2021

Last updated

Jul 9, 2026

Identifiers

CVE-2021-44549

GHSA-c69w-jj56-834w

References

Advisorylists.apache.org Advisorynvd.nist.gov Webgithub.com Webjavaee.github.io Webjavaee.github.io Packagegithub.com

Related vulnerabilities

This CVE is high severity; 3 of 8 other CVEs with CWE-295 are rated as high or higher (top: critical).

CVE-2026-63374CVE-2026-81868CVE-2026-81871GHSA-6hxq-p678-4hr2CVE-2026-55215CVE-2026-54548CVE-2026-63336CVE-2026-8763Browse all CWE-295

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedJul 9, 2026

CVE-2021-44549 — org.apache.sling.commons.…

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2021-44549 in your dependencies?