{"id":"ALPINE-CVE-2026-63073","details":"Issue summary: OpenSSL CMP response validation passed an unexpected response\nsender distinguished name directly as the format string to `ERR_raise_data()`.\n\nImpact summary: A malicious or intercepted CMP endpoint can crash a CMP client\nthat enforces an expected sender or uses a pinned server certificate whose\nsubject becomes the default expected sender.\n\nCWE: CWE-134 (Use of Externally-Controlled Format String)\n\nDescription: When validating a received CMP message, ossl_cmp_msg_check_update()\nconverts the peer-supplied sender distinguished name with X509_NAME_oneline()\nand passes it directly as the format argument to ERR_raise_data(). Percent\ncharacters survive the conversion, so a sender DN such as \"CN=%s%n\" reaches\nBIO_vsnprintf() as an attacker-controlled format string with no matching variadic\narguments. This path is only reached when the caller configures an expected\nsender or pins a server certificate, which is the normal configuration for a\nCMP client validating server responses.\n\nSince the attacker controls the format string but none of the variadic\narguments, such specifiers as %s and %n dereference or write through unrelated\nstack contents and crash the client. The reliable consequence is a denial of\nservice, when the response comes from a malicious or intercepted CMP endpoint.\nThere is no controlled memory write, arbitrary-address read, or reliable path\nto remote code execution.\n\nFIPS impact: no\n\nNo FIPS modules are affected by this issue, as the CMP protocol\nimplementation is outside the OpenSSL FIPS module boundary.","modified":"2026-09-17T17:30:02.479399858Z","published":"2026-08-25T13:19:26.147Z","upstream":["CVE-2026-63073"],"references":[{"type":"ADVISORY","url":"https://security.alpinelinux.org/vuln/CVE-2026-63073"}],"affected":[{"package":{"name":"openssl","ecosystem":"Alpine:v3.21","purl":"pkg:apk/alpine/openssl?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.4.0"},{"fixed":"3.3.7-r1"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2026-63073.json"}},{"package":{"name":"openssl","ecosystem":"Alpine:v3.22","purl":"pkg:apk/alpine/openssl?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.4.0"},{"fixed":"3.5.8-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2026-63073.json"}},{"package":{"name":"openssl","ecosystem":"Alpine:v3.23","purl":"pkg:apk/alpine/openssl?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.4.0"},{"fixed":"3.5.8-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2026-63073.json"}},{"package":{"name":"openssl","ecosystem":"Alpine:v3.24","purl":"pkg:apk/alpine/openssl?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.4.0"},{"fixed":"3.5.8-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2026-63073.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}