{"id":"CVE-2020-20949","aliases":["EUVD-2020-13728","GHSA-7p98-xcgc-gwhj"],"status":"published","title":"Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library...","description":"Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library software expansion for STM32Cube (UM1924). The vulnerability can allow one to use Bleichenbacher's oracle attack to decrypt an encrypted ciphertext by making successive queries to the server using the vulnerable library, resulting in remote information disclosure.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.00938,"percentile":0.61123,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-326","CWE-327"],"published":"2021-01-20T15:42:18Z","modified":"2026-07-09T00:16:53Z","products":[{"vendor":"ietf","product":"public_key_cryptography_standards_\\#1"},{"vendor":"st","product":"stm32cubef0"},{"vendor":"st","product":"stm32cubef1"},{"vendor":"st","product":"stm32cubef2"},{"vendor":"st","product":"stm32cubef3"},{"vendor":"st","product":"stm32cubef4"},{"vendor":"st","product":"stm32cubef7"},{"vendor":"st","product":"stm32cubeg0"},{"vendor":"st","product":"stm32cubeg4"},{"vendor":"st","product":"stm32cubeh7"},{"vendor":"st","product":"stm32cubeide"},{"vendor":"st","product":"stm32cubel0"},{"vendor":"st","product":"stm32cubel1"},{"vendor":"st","product":"stm32cubel4"},{"vendor":"st","product":"stm32cubel4\\+"},{"vendor":"st","product":"stm32cubel5"},{"vendor":"st","product":"stm32cubemonitor"},{"vendor":"st","product":"stm32cubemp1"},{"vendor":"st","product":"stm32cubemx"},{"vendor":"st","product":"stm32cubeprogrammer"},{"vendor":"st","product":"stm32cubewb"},{"vendor":"st","product":"stm32cubewl"}],"references":[{"url":"http://archiv.infsec.ethz.ch/education/fs08/secsem/bleichenbacher98.pdf","tags":["x_refsource_MISC","x_transferred","Technical Description","Third Party Advisory"]},{"url":"https://www.st.com/en/embedded-software/x-cube-cryptolib.html","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://bi-zone.medium.com/silence-will-fall-or-how-it-can-take-2-years-to-get-your-vuln-registered-e6134846f5bb","tags":["x_refsource_MISC","x_transferred","Technical Description","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-20949"},{"url":"http://st.com"},{"url":"http://x-cube-cryptolib.com"},{"url":"https://github.com/advisories/GHSA-7p98-xcgc-gwhj"}],"sources":{"cve":[{"id":"CVE-2020-20949","description":"Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library software expansion for STM32Cube (UM1924). The vulnerability can allow one to use Bleichenbacher's oracle attack to decrypt an encrypted ciphertext by making successive queries to the server using the vulnerable library, resulting in remote information disclosure.","status":"published","published":"2021-01-20T15:42:18Z","modified":"2026-07-09T00:09:53.14Z","updated_at":"2026-11-02T14:35:45.763329Z"}],"euvd":[{"id":"EUVD-2020-13728","description":"Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library software expansion for STM32Cube (UM1924). The vulnerability can allow one to use Bleichenbacher's oracle attack to decrypt an encrypted ciphertext by making successive queries to the server using the vulnerable library, resulting in remote information disclosure.","status":"published","published":"2021-01-20T15:42:18Z","modified":"2026-07-09T00:09:53Z","updated_at":"2026-11-02T18:20:10.095263Z"}],"ghsa":[{"id":"GHSA-7p98-xcgc-gwhj","title":"Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library...","description":"Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library software expansion for STM32Cube (UM1924). The vulnerability can allow one to use Bleichenbacher's oracle attack to decrypt an encrypted ciphertext by making successive queries to the server using the vulnerable library, resulting in remote information disclosure.","status":"published","published":"2022-05-24T17:39:32Z","modified":"2026-07-05T00:32:22Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-326","CWE-327"],"updated_at":"2026-11-02T15:09:14.897479Z"}],"nvd":[{"id":"CVE-2020-20949","description":"Bleichenbacher's attack on PKCS #1 v1.5 padding for RSA in STM32 cryptographic firmware library software expansion for STM32Cube (UM1924). The vulnerability can allow one to use Bleichenbacher's oracle attack to decrypt an encrypted ciphertext by making successive queries to the server using the vulnerable library, resulting in remote information disclosure.","status":"published","published":"2021-01-20T16:15:14.007Z","modified":"2026-07-09T00:16:53.23Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-327"],"updated_at":"2026-11-02T14:06:30.596418Z"}]}}