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osvGoogleOSV:PSF-2023-6
HistoryAug 24, 2023 - 12:00 a.m.

hmac.compare_digest() accumulator not constant-time

2023-08-2400:00:00
Google
osv.dev
7
hmac
python
security
optimization
variable

CVSS3

5.9

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

AI Score

7.1

Confidence

Low

EPSS

0.001

Percentile

24.1%

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.

CVSS3

5.9

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

AI Score

7.1

Confidence

Low

EPSS

0.001

Percentile

24.1%