{"id":"CVE-2026-69249","summary":"python-cryptography: Duplicate self-signed intermediates can cause exponential path-building","details":"python-cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Prior to 49.0.0, when resolving invalid certificate chains that include duplicate copies of self-signed certificates, the processing recursively invokes the same candidate, leading to an exponential blowup. Although the limitation that the chain depth cannot exceed a specified maximum depth prevents unbounded recursion and guarantees termination, an attacker-controlled certificate chain can lead the processing to easily take more than 5s to reject in testing. This amplification could form the basis for a resource exhaustion denial of service attack. The core issue arises in the recursive nature of build_chain_inner, which does not de-duplicate against previously analyzed candidates. As the correctness of validation is not affected, the integrity of a system cannot be compromised through this vector, only its availability. This issue is fixed in 49.0.0.","aliases":["GHSA-jwv3-5hgf-82ww","PYSEC-2026-3553"],"modified":"2026-08-05T08:56:57.104201419Z","published":"2026-08-03T21:26:45.826Z","related":["CGA-mfcr-j98w-873f"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-400"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/69xxx/CVE-2026-69249.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/69xxx/CVE-2026-69249.json"},{"type":"ADVISORY","url":"https://github.com/pyca/cryptography/security/advisories/GHSA-jwv3-5hgf-82ww"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-69249"},{"type":"FIX","url":"https://github.com/pyca/cryptography/commit/4a12cf49675a184e47f912b00b04f3a629283582"},{"type":"FIX","url":"https://github.com/pyca/cryptography/pull/14960"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/pyca/cryptography","events":[{"introduced":"0"},{"fixed":"4a12cf49675a184e47f912b00b04f3a629283582"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"49.0.0"}]}}],"versions":["48.0.0","47.0.0","46.0.1","46.0.0","45.0.0","44.0.0","43.0.0","42.0.0","41.0.0","40.0.0","39.0.0","38.0.0","37.0.0","36.0.0","35.0.0","3.4","3.3","3.2","3.1","3.0","2.9","2.8","2.7","2.6.1","2.6","2.5","2.4.1","2.4","2.3","2.2","2.1","2.0","1.9","1.8","1.7","1.6","1.5","1.4","1.3","1.2","1.1","1.0","0.9","0.8","0.7","0.6","0.5.1","0.5","0.4","0.3","0.2","0.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-69249.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}