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Highest advisory severityCritical 2 vendors · 2 advisories

CVE-2026-84939

Path traversal vulnerability in Apache FreeMarker template loading mechanism, if the attacker can specify an arbitrary malformed locale identifier to FreeMarker, and the localized lookup configuration setting is enabled (it's by default enabled)

CVE-2026-84939: Path traversal vulnerability in Apache FreeMarker template loading mechanism, if the attacker can specify an arbitrary malformed locale…

Compare the source-linked records below. Ratings and product/version details belong to each advisory; they are not a single CVE-wide score or proof that every listed product is affected. How VulniPulse collects and checks evidence.

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CVE-2026-84939 key facts

CISA KEV
Not listed (catalog checked )
Highest advisory severity
Critical
CVSS base score
9.1 (Apache), 7.5 (Red Hat)
Fixed releases
  • Apache: 2.3.35
  • Red Hat: 2.3.35, org.freemarker/freemarker:2.3.35, RHSA-2026:83082, RHSA-2026:83520
Vendor advisories
2 from Apache, Red Hat
VulniPulse record
Published · Updated

Scores, vectors, weaknesses and fixed releases are quoted from vendor advisories that cover only CVE-2026-84939; bulletin-wide values are not repeated here.

Is CVE-2026-84939 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-84939 is not in the CISA KEV catalog (checked ) and no tracked advisory for it reports exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-84939?

Upgrade to a fixed release named by the vendor:

  • Apache: 2.3.35
  • Red Hat: 2.3.35, org.freemarker/freemarker:2.3.35, RHSA-2026:83082, RHSA-2026:83520
  • Users are recommended to upgrade to version 2.3.35. (Apache)
  • To mitigate this vulnerability, disable the localized lookup configuration setting within your Apache FreeMarker deployment. This setting is enabled by default and its deactivation prevents the processing of malformed locale identifiers that could lead to path traversal. Consult your application's documentation for specific instructions on how to configure FreeMarker to disable localized lookup. A restart of the affected application or service will be required for the changes to take effect. Disabling localized lookup may impact applications that rely on this feature for internationalization. (Red Hat)

Vendor advisory comparison

Apache

1 advisory

Red Hat

1 advisory
  • Advisory severityHigh7.5

    High [CVE-2026-84939] Path traversal via malformed locale identifier

    CVE-2026-84939Source published Source updated

    Path traversal vulnerability in Apache FreeMarker template loading mechanism, if the attacker can specify an arbitrary malformed locale identifier to FreeMarker, and the localized lookup configuration setting is enabled (it's by default enabled). Users are recommended to upgrade to version 2.3.35. Disabling localized lookup in previous versions also mitigates this. Note that even in versions affected by this vulnerability, the files that can be loaded remain restricted by the TemplateLoader that FreeMarker is configured to use. In particular, FileTemplateLoader prevents attempts to traverse outside the baseDir specified in its constructor. Other TemplateLoader implementations may allow access outside their designated base directory, but they are still constrained by the underlying…

    Affected products in this advisory
    • Red Hat build of Quarkus 3.27.6.redhat
    • Red Hat build of Quarkus 3.33.4.redhat
    • Red Hat Single Sign-On 7
    Source-reported affected versions
    • 2.2.0
    • 2.3.34
    Source-reported fixed versions
    • 2.3.35
    • org.freemarker/freemarker:2.3.35
    • RHSA-2026:83082
    • RHSA-2026:83520
    Mitigation guidance
    • To mitigate this vulnerability, disable the localized lookup configuration setting within your Apache FreeMarker deployment. This setting is enabled by default and its deactivation prevents the processing of malformed locale identifiers that could lead to path traversal. Consult your application's documentation for specific instructions on how to configure FreeMarker to disable localized lookup. A restart of the affected application or service will be required for the changes to take effect. Disabling localized lookup may impact applications that rely on this feature for internationalization.
    Full advisory and evidenceOpen source bulletin

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