CVE-2026-116266

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{"affected": [{"affectedData": [{"collectionURL": "https://cpan.org/modules", "defaultStatus": "unaffected", "modules": ["MIME::Head"], "packageName": "MIME-tools", "packageURL": "pkg:cpan/MIME-tools", "programFiles": ["lib/MIME/Head.pm", "lib/MIME/Field/ParamVal.pm"], "programRoutines": [{"name": "MIME::Head::multipart_boundary"}, {"name": "MIME::Field::ParamVal::parse_params"}], "repo": "https://salsa.debian.org/dskoll/mime-tools", "versions": [{"lessThan": "5.521", "status": "affected", "version": "5.518", "versionType": "custom"}]}], "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "MIME::Head versions from 5.518 before 5.521 for Perl decode a partly encoded multipart boundary without flagging the parse as ambiguous.\n\nThe multipart_boundary() method decodes RFC 2047 encoded words anywhere in the boundary, but the ambiguity check only fires when the whole value is one encoded word. A boundary such as abc=?us-ascii?Q?def?= is used as abcdef, and ambiguous_content() returns false.\n\nEncoded words are not allowed in parameters, so other mail readers split the message on the literal value. A remote sender can hide an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it."}], "id": "CVE-2026-116266", "lastModified": "2026-11-05T21:18:38.000", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-116266", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-11-05T20:21:08.416154Z", "version": "2.0.3"}}]}, "published": "2026-10-28T18:17:13.017", "references": [{"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "url": "https://metacpan.org/release/DSKOLL/MIME-tools-5.521/changes"}], "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-436"}], "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "type": "Secondary"}]}

{"bugzilla": {"description": "perl-mime-tools: perl-mime-tools: Security filter bypass via partially encoded multipart boundary", "id": "2563056", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2563056"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "status": "draft"}, "cwe": "CWE-115", "details": ["MIME::Head versions from 5.518 before 5.521 for Perl decode a partly encoded multipart boundary without flagging the parse as ambiguous.\nThe multipart_boundary() method decodes RFC 2047 encoded words anywhere in the boundary, but the ambiguity check only fires when the whole value is one encoded word. A boundary such as abc=?us-ascii?Q?def?= is used as abcdef, and ambiguous_content() returns false.\nEncoded words are not allowed in parameters, so other mail readers split the message on the literal value. A remote sender can hide an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it.", "A flaw was found in perl-mime-tools. When parsing email headers, the library decodes partially encoded boundary values in multipart messages without flagging the content as ambiguous. A remote attacker can exploit this flaw by sending a specially crafted email message to bypass email security filters that inspect attachments, while still allowing the recipient's mail client to display the content."], "name": "CVE-2026-116266", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "perl-MIME-tools", "product_name": "Red Hat Enterprise Linux 6"}], "public_date": "2026-10-28T17:32:28Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-116266\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-116266\nhttps://metacpan.org/release/DSKOLL/MIME-tools-5.521/changes"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[5.518,5.521)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "product": "mime::head", "vendor": "perl"}], "created": "2026-10-28T19:00:23.215372+00:00", "updated": "2026-10-30T15:00:15.294843+00:00", "vendors": ["perl", "perl$PRODUCT$mime::head"]}