{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-05-10T04:50:53.265","vulnerabilities":[{"cve":{"id":"CVE-2023-40021","sourceIdentifier":"security-advisories@github.com","published":"2023-08-16T21:15:09.880","lastModified":"2024-11-21T08:18:31.750","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"Oppia is an online learning platform. When comparing a received CSRF token against the expected token, Oppia uses the string equality operator (`==`), which is not safe against timing attacks. By repeatedly submitting invalid tokens, an attacker can brute-force the expected CSRF token character by character. Once they have recovered the token, they can then submit a forged request on behalf of a logged-in user and execute privileged actions on that user's behalf. In particular the function to validate received CSRF tokens is at `oppia.core.controllers.base.CsrfTokenManager.is_csrf_token_valid`. An attacker who can lure a logged-in Oppia user to a malicious website can perform any change on Oppia that the user is authorized to do, including changing profile information; creating, deleting, and changing explorations; etc. Note that the attacker cannot change a user's login credentials. An attack would need to complete within 1 second because every second, the time used in computing the token changes. This issue has been addressed in commit `b89bf80837` which has been included in release `3.3.2-hotfix-2`. Users are advised to upgrade. There are no known workarounds for this vulnerability."}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":1.6,"impactScore":3.6},{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":1.6,"impactScore":3.6}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-203"},{"lang":"en","value":"CWE-208"}]},{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"CWE-203"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:oppia:oppia:*:*:*:*:*:*:*:*","versionStartIncluding":"1.1.0","versionEndExcluding":"3.3.2","matchCriteriaId":"87F65B5D-6454-4E3C-A7A5-F1FEEC6DC78C"},{"vulnerable":true,"criteria":"cpe:2.3:a:oppia:oppia:3.3.2:-:*:*:*:*:*:*","matchCriteriaId":"7B0060B6-6E1F-4B0F-8A6B-3437450C94C3"}]}]}],"references":[{"url":"https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990","source":"security-advisories@github.com","tags":["Product"]},{"url":"https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/oppia/oppia/pull/18769","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532","source":"security-advisories@github.com","tags":["Exploit","Vendor Advisory"]},{"url":"https://github.com/oppia/oppia/blob/3a05c3558a292f3db9e658e60e708c266c003fd0/core/controllers/base.py#L964-L990","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Product"]},{"url":"https://github.com/oppia/oppia/commit/b89bf808378c1236874b5797a7bda32c77b4af23","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://github.com/oppia/oppia/pull/18769","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://github.com/oppia/oppia/security/advisories/GHSA-49jp-pjc3-2532","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Exploit","Vendor Advisory"]}]}}]}