{"cve":"CVE-2020-12403","nvd":{"published":"2021-05-27T19:15:07.953","modified":"2026-06-17T02:51:46.170","status":"Modified","description":"A flaw was found in the way CHACHA20-POLY1305 was implemented in NSS in versions before 3.55. When using multi-part Chacha20, it could cause out-of-bounds reads. This issue was fixed by explicitly disabling multi-part ChaCha20 (which was not functioning correctly) and strictly enforcing tag length. The highest threat from this vulnerability is to confidentiality and system availability.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","score":9.1},"cwes":["CWE-125"],"references":["https://bugzilla.redhat.com/show_bug.cgi?id=1868931","https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.55_release_notes","https://lists.debian.org/debian-lts-announce/2023/02/msg00021.html","https://security.netapp.com/advisory/ntap-20230324-0006/","https://bugzilla.redhat.com/show_bug.cgi?id=1868931"],"products":["mozilla:nss"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2020-12403","score":0.01541,"percentile":0.74926,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}