CVE-2026-28490

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{"bugzilla": {"description": "authlib: Authlib: Information disclosure due to cryptographic padding oracle in JWE RSA1_5", "id": "2448162", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2448162"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.9", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N", "status": "draft"}, "cwe": "CWE-325", "details": ["A flaw was found in Authlib, a Python library for building OAuth and OpenID Connect servers. This cryptographic padding oracle vulnerability, affecting the JSON Web Encryption (JWE) RSA1_5 key management algorithm, could allow a remote attacker to decrypt sensitive information. The vulnerability arises because Authlib registers RSA1_5 without requiring explicit opt-in and bypasses constant-time Bleichenbacher mitigations in the underlying cryptography library."], "name": "CVE-2026-28490", "package_state": [{"cpe": "cpe:/a:redhat:lightspeed_core", "fix_state": "Not affected", "package_name": "lightspeed-core/lightspeed-stack-rhel9", "product_name": "Lightspeed Core"}, {"cpe": "cpe:/a:redhat:ansible_automation_platform:2", "fix_state": "Fix deferred", "package_name": "ansible-automation-platform-25/lightspeed-chatbot-rhel8", "product_name": "Red Hat Ansible Automation Platform 2"}, {"cpe": "cpe:/a:redhat:ansible_automation_platform:2", "fix_state": "Fix deferred", "package_name": "ansible-automation-platform-26/lightspeed-chatbot-rhel9", "product_name": "Red Hat Ansible Automation Platform 2"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-mlflow-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": 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"rhoai/odh-workbench-jupyter-tensorflow-cuda-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-workbench-jupyter-tensorflow-rocm-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:quay:3", "fix_state": "Fix deferred", "package_name": "quay/quay-rhel8", "product_name": "Red Hat Quay 3"}, {"cpe": "cpe:/a:redhat:quay:3", "fix_state": "Fix deferred", "package_name": "quay/quay-rhel9", "product_name": "Red Hat Quay 3"}, {"cpe": "cpe:/a:redhat:satellite:6", "fix_state": "Fix deferred", "package_name": "satellite/foreman-mcp-server-rhel9", "product_name": "Red Hat Satellite 6"}], "public_date": "2026-03-16T17:37:57Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-28490\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-28490\nhttps://github.com/authlib/authlib/commit/48b345f29f6c459f11c6a40162b6c0b742ef2e22\nhttps://github.com/authlib/authlib/releases/tag/v1.6.9\nhttps://github.com/authlib/authlib/security/advisories/GHSA-7432-952r-cw78"], "statement": "This MODERATE vulnerability in Authlib exposes a Bleichenbacher padding oracle in the JWE RSA1_5 implementation. Authlib enables RSA1_5 by default and breaks constant-time protections from the cryptography library. Remote attackers can exploit timing side-channels to decrypt encrypted tokens. Exploitation requires high complexity but no authentication. Impact is high confidentiality loss. Affects versions prior to 1.6.9.", "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.6.9)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "authlib", "source": "cna", "vendor": "authlib"}, "product": "authlib", "vendor": "authlib"}], "analysis": {"en": {"generated_at": "2026-03-17T22:22:36.569501+00:00", "value": {"mitigation_remediation": ["Upgrade Authlib to v1.6.9 or later.", "Disable or remove the RSA1_5 algorithm from the application's JWE key management registry if it is not required.", "Verify that your application does not use the RSA1_5 algorithm by reviewing the key management configuration.", "Test your JWE handling after the upgrade to ensure padding oracle mitigation is active."], "summary": {"action": "Immediate Patch", "impact": "Confidentiality Breach"}, "threat_synthesis": {"affected_systems": "The vulnerability affects the Authlib Python library (authlib:authlib). All versions before 1.6.9 are impacted. The security advisory lists v1.6.9 and later as the fixed release.", "description_and_impact": "Authlib is a Python library that implements OAuth and OpenID Connect servers. A cryptographic padding oracle vulnerability was found in the implementation of the JSON Web Encryption (JWE) RSA1_5 key management algorithm. The library registers RSA1_5 by default without explicit opt\u2011in and removes the constant\u2011time Bleichenbacher mitigation that the underlying cryptography library otherwise provides. As a result, an attacker who can influence the processing of a JWE token can, by exploiting the padding oracle, recover plaintext data or keys, leading to a confidentiality breach and potential further compromise of the system.", "risk_and_exploitability": "The CVSS score is 8.3, indicating a high severity. The EPSS score is less than 1\u202f%, suggesting a low probability of exploitation at the present time. It is not listed in the CISA Known Exploited Vulnerabilities catalog. The attack vector is likely remote: an adversary can craft a JWE token processed by the vulnerable library and repeatedly submit modified ciphertexts to observe padding error responses. Observation of the success of padding operations would allow reconstruction of the underlying plaintext or key material. This exploitation requires the attacker to have the ability to submit JWE requests to an application that uses Authlib."}}}}, "created": "2026-03-17T09:52:24.548573+00:00", "updated": "2026-03-24T10:50:05.028240+00:00", "vendors": ["authlib", "authlib$PRODUCT$authlib"]}