{"id":"DEBIAN-CVE-2021-21401","details":"Nanopb is a small code-size Protocol Buffers implementation in ansi C. In Nanopb before versions 0.3.9.8 and 0.4.5, decoding a specifically formed message can cause invalid `free()` or `realloc()` calls if the message type contains an `oneof` field, and the `oneof` directly contains both a pointer field and a non-pointer field. If the message data first contains the non-pointer field and then the pointer field, the data of the non-pointer field is incorrectly treated as if it was a pointer value. Such message data rarely occurs in normal messages, but it is a concern when untrusted data is parsed. This has been fixed in versions 0.3.9.8 and 0.4.5. See referenced GitHub Security Advisory for more information including workarounds.","modified":"2026-09-15T09:00:53.556373778Z","published":"2021-03-23T18:15:13.160Z","upstream":["CVE-2021-21401"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2021-21401"}],"affected":[{"package":{"name":"nanopb","ecosystem":"Debian:12","purl":"pkg:deb/debian/nanopb?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.4-2"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-21401.json"}},{"package":{"name":"nanopb","ecosystem":"Debian:13","purl":"pkg:deb/debian/nanopb?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.4-2"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-21401.json"}},{"package":{"name":"nanopb","ecosystem":"Debian:14","purl":"pkg:deb/debian/nanopb?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.4-2"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-21401.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L"}]}