{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2021-4456", "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "state": "PUBLISHED", "assignerShortName": "CPANSec", "dateReserved": "2025-05-18T22:36:11.463Z", "datePublished": "2026-02-27T00:16:36.383Z", "dateUpdated": "2026-02-27T16:53:23.671Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://cpan.org/modules", "defaultStatus": "unaffected", "packageName": "Net-CIDR", "product": "Net::CIDR", "programRoutines": [{"name": "addr2cidr"}, {"name": "cidrlookup"}], "repo": "https://github.com/svarshavchik/Net-CIDR", "vendor": "MRSAM", "versions": [{"lessThan": "0.24", "status": "affected", "version": "0", "versionType": "custom"}]}], "descriptions": [{"lang": "en", "value": "Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact.\n\nThe functions `addr2cidr` and `cidrlookup` may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses.\n\nThe documentation advises validating untrusted CIDR strings with the `cidrvalidate` function. However, this mitigation is optional and not enforced by default. In practice, users may call `addr2cidr` or `cidrlookup` with untrusted input and without validation, incorrectly assuming that this is safe."}], "problemTypes": [{"descriptions": [{"cweId": "CWE-704", "description": "CWE-704 Incorrect Type Conversion or Cast", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "shortName": "CPANSec", "dateUpdated": "2026-02-27T00:16:36.383Z"}, "references": [{"tags": ["related"], "url": "https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/"}, {"tags": ["patch"], "url": "https://github.com/svarshavchik/Net-CIDR/commit/e3648c6bc6bdd018f90cca4149c467017d42bd10"}, {"tags": ["release-notes"], "url": "https://metacpan.org/dist/Net-CIDR/changes"}], "solutions": [{"lang": "en", "value": "Use the `cidrvalidate` function on untrusted input before passing to the affected functions or upgrade to version 0.24 or later"}], "source": {"discovery": "UNKNOWN"}, "title": "Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact", "x_generator": {"engine": "cpansec-cna-tool 0.1"}}, "adp": [{"metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-02-27T16:52:58.903437Z", "id": "CVE-2021-4456", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-02-27T16:53:23.671Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2021-4456", "role": "CISA Coordinator", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-02-27T16:52:58.903437Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-02-27T16:44:01.688Z"}}], "cna": {"title": "Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact", "source": {"discovery": "UNKNOWN"}, "affected": [{"repo": "https://github.com/svarshavchik/Net-CIDR", "vendor": "MRSAM", "product": "Net::CIDR", "versions": [{"status": "affected", "version": "0", "lessThan": "0.24", "versionType": "custom"}], "packageName": "Net-CIDR", "collectionURL": "https://cpan.org/modules", "defaultStatus": "unaffected", "programRoutines": [{"name": "addr2cidr"}, {"name": "cidrlookup"}]}], "solutions": [{"lang": "en", "value": "Use the `cidrvalidate` function on untrusted input before passing to the affected functions or upgrade to version 0.24 or later"}], "references": [{"url": "https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/", "tags": ["related"]}, {"url": "https://github.com/svarshavchik/Net-CIDR/commit/e3648c6bc6bdd018f90cca4149c467017d42bd10", "tags": ["patch"]}, {"url": "https://metacpan.org/dist/Net-CIDR/changes", "tags": ["release-notes"]}], "x_generator": {"engine": "cpansec-cna-tool 0.1"}, "descriptions": [{"lang": "en", "value": "Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact.\n\nThe functions `addr2cidr` and `cidrlookup` may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses.\n\nThe documentation advises validating untrusted CIDR strings with the `cidrvalidate` function. However, this mitigation is optional and not enforced by default. In practice, users may call `addr2cidr` or `cidrlookup` with untrusted input and without validation, incorrectly assuming that this is safe."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-704", "description": "CWE-704 Incorrect Type Conversion or Cast"}]}], "providerMetadata": {"orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "shortName": "CPANSec", "dateUpdated": "2026-02-27T00:16:36.383Z"}}}, "cveMetadata": {"cveId": "CVE-2021-4456", "state": "PUBLISHED", "dateUpdated": "2026-02-27T16:53:23.671Z", "dateReserved": "2025-05-18T22:36:11.463Z", "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "datePublished": "2026-02-27T00:16:36.383Z", "assignerShortName": "CPANSec"}, "dataVersion": "5.2"}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact.\n\nThe functions `addr2cidr` and `cidrlookup` may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses.\n\nThe documentation advises validating untrusted CIDR strings with the `cidrvalidate` function. However, this mitigation is optional and not enforced by default. In practice, users may call `addr2cidr` or `cidrlookup` with untrusted input and without validation, incorrectly assuming that this is safe."}, {"lang": "es", "value": "Las versiones de Net::CIDR anteriores a la 0.24 para Perl manejan incorrectamente los ceros iniciales en las direcciones IP CIDR, lo que puede tener un impacto no especificado.\n\nLas funciones `addr2cidr` y `cidrlookup` pueden devolver ceros iniciales en una cadena CIDR, que a su vez pueden ser interpretados como n\u00fameros octales por usuarios posteriores. En algunos casos, un atacante podr\u00eda aprovechar esto para eludir los controles de acceso basados en direcciones IP.\n\nLa documentaci\u00f3n aconseja validar cadenas CIDR no confiables con la funci\u00f3n `cidrvalidate`. Sin embargo, esta mitigaci\u00f3n es opcional y no se aplica por defecto. En la pr\u00e1ctica, los usuarios pueden llamar a `addr2cidr` o `cidrlookup` con entrada no confiable y sin validaci\u00f3n, asumiendo incorrectamente que esto es seguro."}], "id": "CVE-2021-4456", "lastModified": "2026-02-27T17:16:19.903", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 2.5, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}, "published": "2026-02-27T01:16:13.553", "references": [{"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "url": "https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/"}, {"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "url": "https://github.com/svarshavchik/Net-CIDR/commit/e3648c6bc6bdd018f90cca4149c467017d42bd10"}, {"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "url": "https://metacpan.org/dist/Net-CIDR/changes"}], "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-704"}], "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,0.24)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "Net::CIDR", "source": "cna", "vendor": "MRSAM"}, "product": "net::cidr", "vendor": "mrsam"}], "created": "2026-02-27T09:03:17.654759+00:00", "updated": "2026-02-27T09:03:17.654836+00:00", "vendors": ["mrsam", "mrsam$PRODUCT$net::cidr"]}