CVE-2021-34981

{"dataType": "CVE_RECORD", "dataVersion": "5.1", "cveMetadata": {"cveId": "CVE-2021-34981", "assignerOrgId": "99f1926a-a320-47d8-bbb5-42feb611262e", "state": "PUBLISHED", "assignerShortName": "zdi", "dateReserved": "2021-06-17T19:27:05.661Z", "datePublished": "2024-05-07T22:54:49.205Z", "dateUpdated": "2024-08-04T00:26:55.716Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "99f1926a-a320-47d8-bbb5-42feb611262e", "shortName": "zdi", "dateUpdated": "2024-05-07T22:54:49.205Z"}, "title": "Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability", "descriptions": [{"lang": "en", "value": "Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.\n\nThe specific flaw exists within the CMTP module. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel. Was ZDI-CAN-11977."}], "affected": [{"vendor": "Linux", "product": "Kernel", "versions": [{"version": "4.15.0-118-generic", "status": "affected"}], "defaultStatus": "unknown"}], "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-415", "description": "CWE-415: Double Free", "type": "CWE"}]}], "references": [{"url": "https://www.zerodayinitiative.com/advisories/ZDI-21-1223/", "name": "ZDI-21-1223", "tags": ["x_research-advisory"]}], "dateAssigned": "2021-06-30T13:56:51.715Z", "datePublic": "2021-10-26T10:10:16.323Z", "source": {"lang": "en", "value": "Ryota Shiga(@Ga_ryo_) of Flatt Security"}, "metrics": [{"format": "CVSS", "cvssV3_0": {"version": "3.0", "vectorString": "CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H", "baseScore": 7.5, "baseSeverity": "HIGH"}}]}, "adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2021-34981", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2024-05-08T14:56:48.288493Z"}}}], "affected": [{"cpes": ["cpe:2.3:a:linux:kernel:4.15.0-118-generic:*:*:*:*:*:*:*"], "vendor": "linux", "product": "kernel", "versions": [{"status": "affected", "version": "4.15.0-118-generic"}], "defaultStatus": "unknown"}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-04T17:12:51.708Z"}}, {"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T00:26:55.716Z"}, "title": "CVE Program Container", "references": [{"url": "https://www.zerodayinitiative.com/advisories/ZDI-21-1223/", "name": "ZDI-21-1223", "tags": ["x_research-advisory", "x_transferred"]}]}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CVE Program Container", "references": [{"url": "https://www.zerodayinitiative.com/advisories/ZDI-21-1223/", "name": "ZDI-21-1223", "tags": ["x_research-advisory", "x_transferred"]}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T00:26:55.716Z"}}, {"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2021-34981", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2024-05-08T14:56:48.288493Z"}}}], "affected": [{"cpes": ["cpe:2.3:a:linux:kernel:4.15.0-118-generic:*:*:*:*:*:*:*"], "vendor": "linux", "product": "kernel", "versions": [{"status": "affected", "version": "4.15.0-118-generic"}], "defaultStatus": "unknown"}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-05-08T15:03:01.785Z"}, "title": "CISA ADP Vulnrichment"}], "cna": {"title": "Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability", "source": {"lang": "en", "value": "Ryota Shiga(@Ga_ryo_) of Flatt Security"}, "metrics": [{"format": "CVSS", "cvssV3_0": {"version": "3.0", "baseScore": 7.5, "baseSeverity": "HIGH", "vectorString": "CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H"}}], "affected": [{"vendor": "Linux", "product": "Kernel", "versions": [{"status": "affected", "version": "4.15.0-118-generic"}], "defaultStatus": "unknown"}], "datePublic": "2021-10-26T10:10:16.323Z", "references": [{"url": "https://www.zerodayinitiative.com/advisories/ZDI-21-1223/", "name": "ZDI-21-1223", "tags": ["x_research-advisory"]}], "dateAssigned": "2021-06-30T13:56:51.715Z", "descriptions": [{"lang": "en", "value": "Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.\n\nThe specific flaw exists within the CMTP module. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel. Was ZDI-CAN-11977."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-415", "description": "CWE-415: Double Free"}]}], "providerMetadata": {"orgId": "99f1926a-a320-47d8-bbb5-42feb611262e", "shortName": "zdi", "dateUpdated": "2024-05-07T22:54:49.205Z"}}}, "cveMetadata": {"cveId": "CVE-2021-34981", "state": "PUBLISHED", "dateUpdated": "2024-08-04T00:26:55.716Z", "dateReserved": "2021-06-17T19:27:05.661Z", "assignerOrgId": "99f1926a-a320-47d8-bbb5-42feb611262e", "datePublished": "2024-05-07T22:54:49.205Z", "assignerShortName": "zdi"}, "dataVersion": "5.1"}

{"affected": [{"affectedData": [{"defaultStatus": "unknown", "product": "Kernel", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.15.0-118-generic"}]}], "source": "zdi-disclosures@trendmicro.com"}, {"affectedData": [{"cpes": ["cpe:2.3:a:linux:kernel:4.15.0-118-generic:*:*:*:*:*:*:*"], "defaultStatus": "unknown", "product": "kernel", "vendor": "linux", "versions": [{"status": "affected", "version": "4.15.0-118-generic"}]}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "582C74A2-7C5A-40C2-A454-AD25DFDA786D", "versionEndExcluding": "5.10.42", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.\n\nThe specific flaw exists within the CMTP module. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel. Was ZDI-CAN-11977."}, {"lang": "es", "value": "Vulnerabilidad de escalada de privilegios gratuita doble del m\u00f3dulo CMTP Bluetooth del kernel de Linux. Esta vulnerabilidad permite a atacantes locales escalar privilegios en las instalaciones afectadas del kernel de Linux. Un atacante primero debe obtener la capacidad de ejecutar c\u00f3digo con altos privilegios en el sistema de destino para poder explotar esta vulnerabilidad. La falla espec\u00edfica existe dentro del m\u00f3dulo CMTP. El problema surge de la falta de validaci\u00f3n de la existencia de un objeto antes de realizar m\u00e1s operaciones libres sobre el objeto. Un atacante puede aprovechar esta vulnerabilidad para escalar privilegios y ejecutar c\u00f3digo en el contexto del kernel. Era ZDI-CAN-11977."}], "id": "CVE-2021-34981", "lastModified": "2026-06-17T03:56:55.633", "metrics": {"cvssMetricV30": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "HIGH", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H", "version": "3.0"}, "exploitabilityScore": 0.8, "impactScore": 6.0, "source": "zdi-disclosures@trendmicro.com", "type": "Secondary"}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 6.7, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "HIGH", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 0.8, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2021-34981", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2024-05-08T14:56:48.288493Z", "version": "2.0.3"}}]}, "published": "2024-05-07T23:15:13.173", "references": [{"source": "zdi-disclosures@trendmicro.com", "tags": ["Third Party Advisory"], "url": "https://www.zerodayinitiative.com/advisories/ZDI-21-1223/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://www.zerodayinitiative.com/advisories/ZDI-21-1223/"}], "sourceIdentifier": "zdi-disclosures@trendmicro.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-415"}], "source": "zdi-disclosures@trendmicro.com", "type": "Secondary"}]}

{"bugzilla": {"description": "kernel: Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability", "id": "2017077", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2017077"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-416", "details": ["Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.\nThe specific flaw exists within the CMTP module. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel. Was ZDI-CAN-11977.", "A flaw was found in the Linux kernel's CAPI over Bluetooth connection code. An attacker with a local account can escalate privileges when CAPI (ISDN) hardware connection fails."], "mitigation": {"lang": "en:us", "value": "To mitigate these vulnerabilities on the operating system level, disable the Bluetooth functionality via blocklisting kernel modules in the Linux kernel. The kernel modules can be prevented from being loaded by using system-wide modprobe rules. Instructions on how to disable Bluetooth modules are available on the Customer Portal at https://access.redhat.com/solutions/2682931.\nAlternatively, Bluetooth can be disabled within the hardware or at BIOS level which will also provide an effective mitigation as the kernel will not be able to detect that Bluetooth hardware is present on the system."}, "name": "CVE-2021-34981", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2021-10-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-34981\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-34981\nhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3cfdf8fcaafa62a4123f92eb0f4a72650da3a479"], "threat_severity": "Moderate"}

{"created": "2025-07-13T11:22:13.363342+00:00", "updated": "2025-07-13T11:22:13.363401+00:00", "vendors": ["linux", "linux$PRODUCT$kernel"]}