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nss — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2020-12403

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.

Products
nss
Affected versions
Not specified
Fixed versions
2:3.55-1
CVEs
CVE-2020-12403
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 12:29 UTC · Revision 1

Source evidence

DEBIAN-CVE-2020-12403

core-osv · Original source

Published 27 May 2021, 19:15 UTC

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.

osv:DEBIAN-CVE-2020-12403

nss

Fixed versions: 2:3.55-1

nss

Fixed versions: 2:3.55-1

nss

Fixed versions: 2:3.55-1

Complete source record
{
  "id": "2782c042545a1e9a2ab66521980db1e40b6e214f76cfcf94a2a8b31b6d9ae57f",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2020-12403",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2020-12403",
    "summary": "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.",
    "evidence": "osv:DEBIAN-CVE-2020-12403",
    "products": [
      {
        "name": {
          "value": "nss",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2:3.55-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nss",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2:3.55-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nss",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2:3.55-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "DEBIAN-CVE-2020-12403",
      "aliases": [
        "DEBIAN-CVE-2020-12403"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2:3.55-1"
                }
              ]
            }
          ],
          "package": {
            "name": "nss",
            "purl": "pkg:deb/debian/nss?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-12403.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2:3.55-1"
                }
              ]
            }
          ],
          "package": {
            "name": "nss",
            "purl": "pkg:deb/debian/nss?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-12403.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2:3.55-1"
                }
              ]
            }
          ],
          "package": {
            "name": "nss",
            "purl": "pkg:deb/debian/nss?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-12403.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-26T12:00:22.066821319Z",
      "provider": "osv",
      "upstream": [
        "CVE-2020-12403"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2020-12403"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2020-12403",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 451089,
  "published_at": "2021-05-27T19:15:07.953+00:00"
}