{"id":"UBUNTU-CVE-2026-39373","details":"JWCrypto implements JWK, JWS, and JWE specifications using python-cryptography. Prior to 1.5.7, an unauthenticated attacker can exhaust server memory by sending crafted JWE tokens with ZIP compression. The existing patch for CVE-2024-28102  limits input token size to 250KB but does not validate the decompressed output size. An unauthenticated attacker can cause memory exhaustion on memory-constrained systems. A token under the 250KB input limit can decompress to approximately 100MB. This vulnerability is fixed in 1.5.7.","modified":"2026-05-20T16:12:58.477765137Z","published":"2026-04-07T20:16:00Z","upstream":["CVE-2026-39373"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-39373"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-39373"},{"type":"REPORT","url":"https://github.com/latchset/jwcrypto/security/advisories/GHSA-fjrm-76x2-c4q4"}],"affected":[{"package":{"name":"python-jwcrypto","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/python-jwcrypto?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.2.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python-jwcrypto","binary_version":"0.2.1-1"},{"binary_name":"python3-jwcrypto","binary_version":"0.2.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"}},{"package":{"name":"python-jwcrypto","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/python-jwcrypto?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.3.2-1","0.4.2-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python-jwcrypto","binary_version":"0.4.2-1"},{"binary_name":"python3-jwcrypto","binary_version":"0.4.2-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"}},{"package":{"name":"python-jwcrypto","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/python-jwcrypto?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.6.0-1","0.6.0-2"],"ecosystem_specific":{"binaries":[{"binary_version":"0.6.0-2","binary_name":"python3-jwcrypto"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"}},{"package":{"name":"python-jwcrypto","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/python-jwcrypto?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.8.0-1","1.0.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-jwcrypto","binary_version":"1.0.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"}},{"package":{"name":"python-jwcrypto","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-jwcrypto?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.0-1","1.5.4-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-jwcrypto","binary_version":"1.5.4-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"}},{"package":{"name":"python-jwcrypto","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/python-jwcrypto?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.6-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-jwcrypto","binary_version":"1.5.6-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"}},{"package":{"name":"python-jwcrypto","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/python-jwcrypto?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.6-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-jwcrypto","binary_version":"1.5.6-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"type":"Ubuntu","score":"medium"}]}