VulnerabilityPublished 6 Oct 2025

CVE-2025-61766: weirdgloop mediawiki-extensions-Bucket · Uncontrolled Recursion

Affects weirdgloop mediawiki-extensions-BucketSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 1.0.0 when convenient.

Data as of 26 Oct 2026, 09:08 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.0.0

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

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

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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Oct 2025
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 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

Upgrade weirdgloop mediawiki-extensions-Bucket to 1.0.0.

Affected software

Product	Affected	Fixed in
weirdgloop mediawiki-extensions-Bucket	Affected <1.0.0	Fixed in 1.0.0

AI-suggested

To mitigate CVE-2025-61766, European organizations should immediately upgrade the weirdgloop MediaWiki 'Bucket' extension to version 1.0.0 or later, where the infinite recursion issue is patched. If upgrading is not immediately feasible, organizations should restrict access to the bucket query functionality to trusted users only, implementing strict access controls and monitoring query usage for anomalous patterns. Employing web application firewalls (WAFs) with custom rules to detect and block queries using the '!=' comparator in bucket queries can provide temporary protection. Additionally, organizations should audit user privileges to minimize the number of users able to perform such queries, enforce strong authentication mechanisms, and monitor MediaWiki logs for signs of exploitation attempts. Regular backups and incident response plans should be updated to handle potential DoS incidents. Finally, staying informed on updates from the vendor and applying patches promptly is critical to maintaining security.

Description

Bucket is a MediaWiki extension to store and retrieve structured data on articles. Prior to version 1.0.0, infinite recursion can occur if a user queries a bucket using the `!=` comparator. This will result in PHP's call stack limit exceeding, and/or increased memory consumption, potentially leading to a denial of service. Version 1.0.0 contains a patch for the issue.

Impact

For European organizations, the primary impact of CVE-2025-61766 is the potential denial of service on MediaWiki platforms using the vulnerable 'Bucket' extension. This can disrupt internal knowledge bases, documentation portals, or public-facing wikis, affecting business continuity and operational efficiency. Organizations relying on MediaWiki for collaborative content management, especially in government, education, and research sectors, may experience outages or degraded performance, impacting user productivity and service availability. Since the vulnerability requires authenticated access, insider threats or compromised user accounts could be leveraged to exploit this issue. While no data breach or integrity compromise is expected, the loss of availability could hinder critical workflows and damage organizational reputation. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits following public disclosure. European entities with strict uptime and service availability requirements must prioritize mitigation to avoid operational disruptions.

CWE-674Uncontrolled Recursion (opens in a new tab)
Class weakness
The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
Implementation
Ensure that an end condition will be reached under all logic conditions. The end condition may include checking against the depth of recursion and exiting with an error if the recursion goes too deep. The complexity of the end condition contributes to the effectiveness of this action.
Implementation
Increase the stack size.
Attack patterns
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Oct 2025, 16:22 UTC

WeaknessesCWE-674

Technical details

References

Community reviews

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