VulnerabilityPublished 10 Sep 2026

CVE-2026-84939: Apache FreeMarker · Relative Path Traversal

Affects Apache FreeMarkerSource CVE Database V5

Not known to be exploited · CVSS 9.1 Critical · fixed in 2.3.35 : patch Apache FreeMarker as a priority.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

9.1Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS

0.8% chance of exploitation in 30 days – higher than 58% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers can reliably automate steps 1–4 of the kill chain
Technical impact: Total control over the software or total information disclosure

CISA SSVC assessment, 2026-09-10.

Patch

Available – fixed in 2.3.35

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Apache Software FoundationApache FreeMarker	Affected >=2.2.0 <=2.3.34	Fixed in–
Apache Software FoundationApache FreeMarker	Affected >=2.2.0 <=2.3.34	Fixed in–
MavenApache Software Foundation/org.freemarker:freemarker`pkg:maven/Apache Software Foundation/org.freemarker:freemarker`Other threats	Affected >=2.2.0 <=2.3.34	Fixed in–
MavenApache Software Foundation/org.freemarker:freemarker-gae`pkg:maven/Apache Software Foundation/org.freemarker:freemarker-gae`Other threats	Affected >=2.2.0 <=2.3.34	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Users should upgrade Apache FreeMarker to version 2.3.35, where this vulnerability is fixed. Alternatively, disabling the localized lookup feature in affected versions mitigates the issue. No other specific mitigations are indicated.

Description

CVE-2026-84939 is a critical path traversal vulnerability in Apache FreeMarker's template loading mechanism. It occurs when an attacker specifies a malformed locale identifier while localized lookup is enabled (enabled by default). This affects versions from 2.2.0 through 2.3.34. The vulnerability allows unauthorized reading of files within the constraints of the configured TemplateLoader. Users should upgrade to version 2.3.35 or disable localized lookup to mitigate the issue.

Impact

The vulnerability allows an unauthenticated attacker to perform path traversal and potentially read sensitive files accessible via the template loader's storage mechanism. The CVSS score of 9.1 indicates high confidentiality and integrity impact with no required privileges or user interaction. However, the actual file access is limited by the configured TemplateLoader, which may reduce the risk depending on deployment.

Summary

Apache FreeMarker versions 2.2.0 through 2.3.34 contain a path traversal vulnerability (CWE-23) in the template loading mechanism. If an attacker can supply a malformed locale identifier and localized lookup is enabled, they may cause FreeMarker to load unintended files. The scope of accessible files is limited by the TemplateLoader implementation; for example, FileTemplateLoader restricts access to its base directory, but other loaders may allow broader access constrained by their underlying storage. The vulnerability is fixed in version 2.3.35, and disabling localized lookup in earlier versions also mitigates the risk.

CWE-23Relative Path Traversal (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
Operation · Firewall
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Relative Path Traversal (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:00 UTC

WeaknessesCWE-23

Technical details

References

Community reviews

Related threats