An issue was discovered in compare_digest in Lib/hmac.py in Python through 3.9.1. Constant-time-defeating optimisations were possible in the accumulator variable in hmac.compare_digest.
2.7.18-1~20.04.73.8.10-0ubuntu1~20.042.7.18-13ubuntu1.53.4.0-13.4.0-2ubuntu13.4.0-2ubuntu1.13.4.3-1ubuntu1~14.04.13.4.3-1ubuntu1~14.04.33.4.3-1ubuntu1~14.04.43.4.3-1ubuntu1~14.04.53.4.3-1ubuntu1~14.04.63.4.3-1ubuntu1~14.04.73.4.3-1ubuntu1~14.04.7+esm10+24 more3.5.2-2ubuntu0~16.04.4~14.04.1+esm12.7.12-1ubuntu0~16.04.18+esm73.5.2-2ubuntu0~16.04.13+esm112.7.17-1~18.04ubuntu1.13+esm23.6.9-1~18.04ubuntu1.13+esm23.7.5-2ubuntu1~18.04.2+esm3Exploitability
AV:NAC:HPR:NUI:NScope
S:UImpact
C:HI:NA:NCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N