CVE-2026-22712VulnerabilityPublished 9 Jan 2026

CVE-2026-22712: The Wikimedia Foundation Mediawiki – ApprovedRevs Extension · Improper Encoding or Escaping of Output

Affects The Wikimedia Foundation Mediawiki – ApprovedRevs ExtensionSource CVE Database V5

Not known to be exploited · CVSS 2.3 Low.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

2.3Low

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 14% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: Present
Privileges Required: None
User Interaction: Passive
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: Low
Subsequent system integrity: Low
Subsequent system availability: Low

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: Present: The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: a race condition must be won to successfully exploit the vulnerability (the successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker, or the attack may need to be launched multiple times against a single target before being successful); the attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
Subsequent system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Subsequent System.
Subsequent system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Subsequent System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Subsequent System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Jan 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 2026-10-25.

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 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
The Wikimedia FoundationMediawiki - ApprovedRevs Extension	Affected =1.45 =1.44 =1.43 =1.39	Fixed in–

AI-suggested

To mitigate CVE-2026-22712, European organizations should take several specific steps beyond generic advice: 1) Immediately audit and restrict user permissions on Mediawiki installations to limit who can edit or add content, especially in the ApprovedRevs Extension context. 2) Implement strict input validation and sanitization on all user inputs that interact with the magic word replacement functionality to prevent injection of malicious content. 3) Monitor wiki edits and revisions for unusual or suspicious changes that could indicate exploitation attempts. 4) Deploy web application firewalls (WAFs) with custom rules to detect and block attempts to exploit output encoding flaws. 5) Stay informed about official patches or updates from the Wikimedia Foundation and apply them promptly once available. 6) Consider temporarily disabling the ApprovedRevs Extension if feasible until a patch is released. 7) Educate wiki administrators and users about the risks of input manipulation and encourage vigilance in reviewing content changes. These targeted actions will reduce the attack surface and help prevent exploitation of this vulnerability.

Description

Improper Encoding or Escaping of Output due to magic word replacement in ParserAfterTidy vulnerability in The Wikimedia Foundation Mediawiki - ApprovedRevs Extension allows Input Data Manipulation.This issue affects Mediawiki - ApprovedRevs Extension: 1.45, 1.44, 1.43, 1.39.

Impact

For European organizations, the impact of CVE-2026-22712 is relatively limited due to its low severity score and the requirement for user interaction. However, organizations relying on Mediawiki with the ApprovedRevs Extension for internal or public knowledge management could face risks of content manipulation or defacement. This could undermine trust in the integrity of information, especially in governmental, educational, or research institutions that use Mediawiki extensively. While the vulnerability does not directly lead to data exfiltration or system compromise, manipulated content could be used for social engineering or misinformation campaigns. The low impact on confidentiality and availability means critical systems are unlikely to be disrupted, but reputational damage and misinformation risks remain. European organizations with public-facing wikis or collaborative platforms should be aware of this threat and prepare to mitigate it promptly.

CWE-116Improper Encoding or Escaping of Output (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Parameterization
If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.
Architecture and Design · Implementation
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
OWASP Cheat Sheets
Content Security Policy (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
Query Parameterization (opens in a new tab)
OWASP ASVS 4.0.3
V14.4.6 (opens in a new tab)
V14.4.4 (opens in a new tab)
V14.4.2 (opens in a new tab)
Attack patterns
Cross Zone Scripting (opens in a new tab)
User-Controlled Filename (opens in a new tab)
Web Server Logs Tampering (opens in a new tab)
AJAX Footprinting (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 9 Jan 2026, 10:32 UTC

WeaknessesCWE-116

Technical details

References

Community reviews

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