VulnerabilityPublished 21 Feb 2026Updated 23 Feb 2026

CVE-2026-26047: moodle · Uncontrolled Resource Consumption

Affects moodleSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium · fixed in 5.1.2 : update moodle when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.1.2, 5.0.5, 4.5.9

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 21 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

Upgrade moodle to 5.1.2, 5.0.5 or 4.5.9.

Affected software

Product	Affected	Fixed in
GitHubmoodle`pkg:github/moodle`Other threats	Affected <4.5.9 >=5.0.0 <5.0.5 >=5.1.0 <5.1.2	Fixed in 4.5.9 5.0.5 5.1.2

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

AI-suggested

To mitigate CVE-2026-26047, organizations should first apply any available patches or updates from Moodle that address this vulnerability. If patches are not yet available, administrators should consider disabling the TeX formula editor or the mimetex rendering feature temporarily to prevent exploitation. Implementing strict resource usage limits and execution timeouts at the server or application level for TeX rendering processes can help contain resource consumption. Monitoring server performance and setting alerts for unusual CPU or memory spikes related to mimetex processes can enable early detection of exploitation attempts. Additionally, enforcing strong authentication controls, including multi-factor authentication and regular credential audits, reduces the risk of unauthorized access. Educating users about responsible use of formula editors and monitoring submitted content for suspicious patterns can further reduce risk. Finally, segregating Moodle services on dedicated infrastructure with resource quotas can limit the impact of any exploitation.

Description

A denial-of-service vulnerability was identified in Moodle’s TeX formula editor. When rendering TeX content using mimetex, insufficient execution time limits could allow specially crafted formulas to consume excessive server resources. An authenticated user could abuse this behavior to degrade performance or cause service interruption.

Impact

The primary impact of CVE-2026-26047 is denial of service through resource exhaustion. Organizations running affected Moodle versions may experience degraded performance or complete service outages, disrupting e-learning activities. This can affect students, educators, and administrative staff relying on Moodle for course delivery and management. The vulnerability requires authenticated access, so attackers must have valid user credentials, which limits exposure but does not eliminate risk, especially in environments with large user bases or weak credential controls. The disruption can lead to loss of productivity, reputational damage, and potential financial costs related to downtime and incident response. Since Moodle is widely used globally in educational institutions, the scope of impact is significant, particularly in regions with high Moodle adoption. The lack of confidentiality or integrity impact reduces risks related to data breaches but does not diminish the operational consequences of service unavailability.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Feb 2026, 13:23 UTC

Technical details

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