CVE-2026-34877

{"dataType": "CVE_RECORD", "cveMetadata": {"state": "PUBLISHED", "cveId": "CVE-2026-34877", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "assignerShortName": "mitre", "dateUpdated": "2026-04-02T17:52:53.594Z", "dateReserved": "2026-03-31T00:00:00.000Z", "datePublished": "2026-04-02T00:00:00.000Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-04-02T16:37:49.459Z"}, "descriptions": [{"lang": "en", "value": "An issue was discovered in Mbed TLS versions from 2.19.0 up to 3.6.5, Mbed TLS 4.0.0. Insufficient protection of serialized SSL context or session structures allows an attacker who can modify the serialized structures to induce memory corruption, leading to arbitrary code execution. This is caused by Incorrect Use of Privileged APIs."}], "affected": [{"vendor": "n/a", "product": "n/a", "versions": [{"version": "n/a", "status": "affected"}]}], "references": [{"url": "https://mbed-tls.readthedocs.io/en/latest/security-advisories/"}, {"url": "https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-serialized-data/"}], "problemTypes": [{"descriptions": [{"type": "text", "lang": "en", "description": "n/a"}]}]}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-250", "lang": "en", "description": "CWE-250 Execution with Unnecessary Privileges"}]}, {"descriptions": [{"type": "CWE", "cweId": "CWE-502", "lang": "en", "description": "CWE-502 Deserialization of Untrusted Data"}]}], "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-04-02T17:51:48.970447Z", "id": "CVE-2026-34877", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-02T17:52:53.594Z"}}]}, "dataVersion": "5.2"}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2026-34877", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-04-02T17:51:48.970447Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-250", "description": "CWE-250 Execution with Unnecessary Privileges"}]}, {"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-502", "description": "CWE-502 Deserialization of Untrusted Data"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-02T17:50:56.222Z"}}], "cna": {"affected": [{"vendor": "n/a", "product": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}], "references": [{"url": "https://mbed-tls.readthedocs.io/en/latest/security-advisories/"}, {"url": "https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-serialized-data/"}], "descriptions": [{"lang": "en", "value": "An issue was discovered in Mbed TLS versions from 2.19.0 up to 3.6.5, Mbed TLS 4.0.0. Insufficient protection of serialized SSL context or session structures allows an attacker who can modify the serialized structures to induce memory corruption, leading to arbitrary code execution. This is caused by Incorrect Use of Privileged APIs."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "text", "description": "n/a"}]}], "providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-04-02T16:37:49.459Z"}}}, "cveMetadata": {"cveId": "CVE-2026-34877", "state": "PUBLISHED", "dateUpdated": "2026-04-02T17:52:53.594Z", "dateReserved": "2026-03-31T00:00:00.000Z", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "datePublished": "2026-04-02T00:00:00.000Z", "assignerShortName": "mitre"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"product": "n/a", "vendor": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}], "source": "cve@mitre.org"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*", "matchCriteriaId": "60B71009-7D02-4B21-AB91-F0B821214B20", "versionEndExcluding": "3.6.6", "versionStartIncluding": "2.19.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:trustedfirmware:mbed_tls:4.0.0:*:*:*:*:*:*:*", "matchCriteriaId": "26ECBD35-D500-4CF2-A7F5-0C91A5F39274", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "An issue was discovered in Mbed TLS versions from 2.19.0 up to 3.6.5, Mbed TLS 4.0.0. Insufficient protection of serialized SSL context or session structures allows an attacker who can modify the serialized structures to induce memory corruption, leading to arbitrary code execution. This is caused by Incorrect Use of Privileged APIs."}, {"lang": "es", "value": "Se descubri\u00f3 un problema en las versiones de Mbed TLS desde la 2.19.0 hasta la 3.6.5, y en Mbed TLS 4.0.0. La protecci\u00f3n insuficiente de las estructuras de contexto SSL o de sesi\u00f3n serializadas permite a un atacante que puede modificar las estructuras serializadas inducir corrupci\u00f3n de memoria, lo que lleva a ejecuci\u00f3n de c\u00f3digo arbitrario. Esto es causado por el Uso Incorrecto de APIs Privilegiadas."}], "id": "CVE-2026-34877", "lastModified": "2026-07-24T21:10:00.143", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-34877", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-04-02T17:51:48.970447Z", "version": "2.0.3"}}]}, "published": "2026-04-02T17:16:26.927", "references": [{"source": "cve@mitre.org", "tags": ["Vendor Advisory"], "url": "https://mbed-tls.readthedocs.io/en/latest/security-advisories/"}, {"source": "cve@mitre.org", "tags": ["Vendor Advisory"], "url": "https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-serialized-data/"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-250"}, {"lang": "en", "value": "CWE-502"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.19.0,3.6.5]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "4.0.0"}}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "n/a", "source": "cna", "vendor": "n/a"}, "product": "mbedtls", "vendor": "mbed"}], "analysis": {"en": {"generated_at": "2026-04-07T01:51:28.643483+00:00", "value": {"mitigation_remediation": ["Apply the latest Mbed TLS patch or upgrade to a fixed release", "Review Arm\u2019s Mbed TLS security advisories for update details", "If a patch is not immediately available, restrict or block traffic that transmits serialized SSL context data to isolate the affected systems"], "summary": {"action": "Immediate Patch", "impact": "Remote Code Execution"}, "threat_synthesis": {"affected_systems": "Arm\u2019s Mbed TLS library is affected. All actively supported releases from 2.19.0 up to 3.6.5, and the 4.0.0 release, are vulnerable. Users of these versions should identify which exact build they run and plan an update.", "description_and_impact": "The vulnerability arises from insufficient protection of serialized SSL context or session data in Mbed TLS. An attacker who can alter these serialized structures can trigger memory corruption, enabling arbitrary code execution. This is a serious flaw mapped to CWE-250 and CWE-502, reflecting improper privilege handling and insecure deserialization.", "risk_and_exploitability": "The CVSS score is 9.8, indicating catastrophic impact. The EPSS score is below 1\u202f% and the issue is not yet listed in the CISA KEV catalog. Based on the description, the likely attack vector is remote, requiring an attacker to supply a tampered SSL context over the network; this can then be deserialized by the library, causing memory corruption and granting the attacker control of the process."}}}}, "created": "2026-04-03T08:58:19.704458+00:00", "updated": "2026-04-07T07:56:20.074842+00:00", "vendors": ["mbed", "mbed$PRODUCT$mbedtls"]}