{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-33936", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-03-24T19:50:52.103Z", "datePublished": "2026-03-27T22:08:22.868Z", "dateUpdated": "2026-03-27T22:08:22.868Z"}, "containers": {"cna": {"title": "python-ecdsa: Denial of Service via improper DER length validation in crafted private keys", "problemTypes": [{"descriptions": [{"cweId": "CWE-20", "lang": "en", "description": "CWE-20: Improper Input Validation", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-130", "lang": "en", "description": "CWE-130: Improper Handling of Length Parameter Inconsistency", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "version": "3.1"}}], "references": [{"name": "https://github.com/tlsfuzzer/python-ecdsa/security/advisories/GHSA-9f5j-8jwj-x28g", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/tlsfuzzer/python-ecdsa/security/advisories/GHSA-9f5j-8jwj-x28g"}, {"name": "https://github.com/tlsfuzzer/python-ecdsa/commit/bd66899550d7185939bf27b75713a2ac9325a9d3", "tags": ["x_refsource_MISC"], "url": "https://github.com/tlsfuzzer/python-ecdsa/commit/bd66899550d7185939bf27b75713a2ac9325a9d3"}, {"name": "https://github.com/tlsfuzzer/python-ecdsa/releases/tag/python-ecdsa-0.19.2", "tags": ["x_refsource_MISC"], "url": "https://github.com/tlsfuzzer/python-ecdsa/releases/tag/python-ecdsa-0.19.2"}], "affected": [{"vendor": "tlsfuzzer", "product": "python-ecdsa", "versions": [{"version": "< 0.19.2", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-27T22:08:22.868Z"}, "descriptions": [{"lang": "en", "value": "The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue."}], "source": {"advisory": "GHSA-9f5j-8jwj-x28g", "discovery": "UNKNOWN"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue."}], "id": "CVE-2026-33936", "lastModified": "2026-03-30T13:26:07.647", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-03-27T23:17:13.733", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/tlsfuzzer/python-ecdsa/commit/bd66899550d7185939bf27b75713a2ac9325a9d3"}, {"source": "security-advisories@github.com", "url": "https://github.com/tlsfuzzer/python-ecdsa/releases/tag/python-ecdsa-0.19.2"}, {"source": "security-advisories@github.com", "url": "https://github.com/tlsfuzzer/python-ecdsa/security/advisories/GHSA-9f5j-8jwj-x28g"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-130"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{"bugzilla": {"description": "python-ecdsa: ecdsa: Denial of Service via crafted DER input", "id": "2452539", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2452539"}, "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:N/A:L", "status": "draft"}, "cwe": "CWE-130", "details": ["The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.", "A flaw was found in the `ecdsa` Python package, which is used for cryptographic operations. A remote attacker can exploit this vulnerability by sending a specially crafted data input, known as Distinguished Encoding Rules (DER). This malformed input can cause applications that process untrusted cryptographic keys to crash, leading to a denial of service."], "name": "CVE-2026-33936", "package_state": [{"cpe": "cpe:/a:redhat:ansible_automation_platform:2", "fix_state": "Out of support scope", "package_name": "python-ecdsa", "product_name": "Red Hat Ansible Automation Platform 2"}, {"cpe": "cpe:/a:redhat:satellite:6", "fix_state": "Fix deferred", "package_name": "python-ecdsa", "product_name": "Red Hat Satellite 6"}, {"cpe": "cpe:/a:redhat:satellite:6", "fix_state": "Fix deferred", "package_name": "satellite-capsule:el8/python-ecdsa", "product_name": "Red Hat Satellite 6"}, {"cpe": "cpe:/a:redhat:rhui:4::el8", "fix_state": "Out of support scope", "package_name": "python-ecdsa", "product_name": "Red Hat Update Infrastructure 4 for Cloud Providers"}], "public_date": "2026-03-27T22:08:22Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-33936\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-33936\nhttps://github.com/tlsfuzzer/python-ecdsa/commit/bd66899550d7185939bf27b75713a2ac9325a9d3\nhttps://github.com/tlsfuzzer/python-ecdsa/releases/tag/python-ecdsa-0.19.2\nhttps://github.com/tlsfuzzer/python-ecdsa/security/advisories/GHSA-9f5j-8jwj-x28g"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,0.19.2)"}}], "enrichment": {"confidence": 81.0, "confidence_source": "matching", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 81.0, "source": "matching"}]}, "original": {"product": "python-ecdsa", "source": "cna", "vendor": "tlsfuzzer"}, "product": "ecdsa", "vendor": "tlsfuzzer"}], "analysis": {"en": {"generated_at": "2026-03-28T05:27:30.465308+00:00", "value": {"mitigation_remediation": ["Update the python-ecdsa package to version 0.19.2 or later.", "Encapsulate calls to SigningKey.from_der() within try\u2011except blocks that catch generic exceptions (e.g., IndexError, UnexpectedDER) and treat them as malformed input rather than crashing the application."], "summary": {"action": "Immediate Patch", "impact": "Denial of Service via malformed DER private key parsing"}, "threat_synthesis": {"affected_systems": "All releases of the python\u2011ecdsa package prior to version 0.19.2, distributed via PyPI and maintained by the tlsfuzzer project. Users employing the SigningKey.from_der() API in their Python applications are potentially impacted. The issue does not affect other packages or systems independent of this library.", "description_and_impact": "An improper validation of the DER length field in the ecdsa package\u2019s low\u2011level parser can cause the internal function ecdsa.der.remove_octet_string() to accept incorrectly truncated data. When a private key is loaded through SigningKey.from_der(), an IndexError is raised instead of a cleanly rejected exception such as UnexpectedDER or ValueError. The result is an application crash when it does not handle the unexpected exception, providing an avenue for an attacker to cause a denial of service.\n\nThe flaw is a classic input validation issue (CWE\u2011130) and a potential buffer over\u2011read (CWE\u201120). The vulnerability does not grant code execution or data exfiltration; it only disrupts availability.\n\nThe CVSS score of 5.3 reflects moderate impact: the exploitation requires an attacker to supply a crafted private key to the application. Therefore it is not a high\u2011severity threat but should be addressed promptly to prevent DoS conditions.", "risk_and_exploitability": "The vulnerability\u2019s CVSS score of 5.3 indicates a moderate risk level. EPSS data is not available, and the flaw is not cataloged in CISA\u2019s KEV list, suggesting limited public exploitation. Exploitation relies solely on the ability to feed a crafted DER private key to the target application; no additional privileges or network conditions are required. If an application does not swallow the unexpected IndexError, the application will terminate, resulting in a denial of service for users or services dependent on that executable. The safest defense is to rely on the vendor\u2019s fix or to handle the exceptions gracefully."}}}}, "created": "2026-03-29T20:29:29.771541+00:00", "updated": "2026-03-30T07:59:14.575636+00:00", "vendors": ["tlsfuzzer", "tlsfuzzer$PRODUCT$ecdsa"]}