{"cve":"CVE-2021-23841","nvd":{"published":"2021-02-16T17:15:13.377","modified":"2026-06-17T03:38:54.823","status":"Modified","description":"The OpenSSL public API function X509_issuer_and_serial_hash() attempts to create a unique hash value based on the issuer and serial number data contained within an X509 certificate. However it fails to correctly handle any errors that may occur while parsing the issuer field (which might occur if the issuer field is maliciously constructed). This may subsequently result in a NULL pointer deref and a crash leading to a potential denial of service attack. The function X509_issuer_and_serial_hash() is never directly called by OpenSSL itself so applications are only vulnerable if they use this function directly and they use it on certificates that may have been obtained from untrusted sources. OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","score":5.9},"cwes":["CWE-476"],"references":["http://seclists.org/fulldisclosure/2021/May/67","http://seclists.org/fulldisclosure/2021/May/68","http://seclists.org/fulldisclosure/2021/May/70","https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf","https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=122a19ab48091c657f7cb1fb3af9fc07bd557bbf"],"products":["apple:ipados","apple:iphone_os","apple:macos","apple:safari","debian:debian_linux","netapp:oncommand_insight","netapp:oncommand_workflow_automation","netapp:snapcenter","openssl:openssl","oracle:business_intelligence","oracle:communications_cloud_native_core_policy","oracle:enterprise_manager_for_storage_management","oracle:enterprise_manager_ops_center","oracle:essbase","oracle:graalvm","oracle:jd_edwards_world_security","oracle:mysql_enterprise_monitor","oracle:mysql_server","oracle:peoplesoft_enterprise_peopletools","oracle:zfs_storage_appliance_kit","siemens:sinec_ins","tenable:nessus_network_monitor","tenable:tenable.sc"],"source":"nvd","synced_at":"2026-10-19T21:15:50.279857260+00:00"},"epss":{"cve":"CVE-2021-23841","score":0.0741,"percentile":0.94439,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-84rm-qf37-fgc2","url":"https://osv.dev/vulnerability/GHSA-84rm-qf37-fgc2","summary":"Integer Overflow in openssl-src","modified":"2023-11-08T04:05:13.735348Z","packages":[{"ecosystem":"crates.io","name":"openssl-src","purl":"pkg:cargo/openssl-src","ranges":["<111.14.0"],"fixed":["111.14.0"]}]},{"id":"RUSTSEC-2021-0058","url":"https://osv.dev/vulnerability/RUSTSEC-2021-0058","summary":"Null pointer deref in `X509_issuer_and_serial_hash()`","modified":"2023-11-08T04:05:13.735348Z","packages":[{"ecosystem":"crates.io","name":"openssl-src","purl":"pkg:cargo/openssl-src","ranges":[">=0.0.0-0 <111.14.0"],"fixed":["111.14.0"]}]}],"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."]}