Moodle: Improper Neutralization of Formula Elements in a CSV File
CVE-2025-67851 is a high-severity improper neutralization of formula elements in a CSV file vulnerability in Moodle, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 4.1.22, 4.4.11, 4.5.8 as the first without the flaw, so updating Moodle to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.29% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Moodle to 4.1.22 or 4.4.11 or 4.5.8 or 5.0.4, whichever matches your release line, or a later version.
- Read the advisory on moodle.org for workarounds and exact fixed builds.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Moodle | Moodle | before 4.1.22; 4.4.0 up to, but not including, 4.4.11; 4.5.0 up to, but not including, 4.5.8; 5.0.0 up to, but not including, 5.0.4; 5.1.0 | 4.1.22, 4.4.11, 4.5.8, 5.0.4 |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.1 | Medium | CNA (puiterwijk.org) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
A flaw was found in moodle. This formula injection vulnerability occurs when data fields are exported without proper escaping. A remote attacker could exploit this by providing malicious data that, when exported and opened in a spreadsheet, allows arbitrary formulas to execute. This can lead to compromised data integrity and unintended operations within the spreadsheet.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Formula Elements in a CSV File
The product saves user-provided information into a Comma-Separated Value (CSV) file, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as a command when the file is opened by a spreadsheet product.
How developers prevent this class of flaw
- When generating CSV output, ensure that formula-sensitive metacharacters are effectively escaped or removed from all data before storage in the resultant CSV. Risky characters include '=' (equal), '+' (plus), '-' (minus), and '@' (at).
- If a field starts with a formula character, prepend it with a ' (single apostrophe), which prevents Excel from executing the formula.
- Certain implementations of spreadsheet software might disallow formulas from executing if the file is untrusted, or if the file is not authored by the current user.
More Improper Neutralization of Formula Elements in a CSV File vulnerabilities (CWE-1236)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- access.redhat.com/security/cve/CVE-2025-67851Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2423841Issue Tracking, Third Party Advisory
Other vulnerabilities in Moodle
- 8.8 High severity
- 7.2 High severity
- 7.2 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.1 High severity
Recent Improper Neutralization of Formula Elements in a CSV File vulnerabilities
- 9.0 Critical severity
- 7.3 High severity
- 8.0 High severity
- 8.8 High severity
- 8.0 High severity
- 8.0 High severity
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