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Description
In Nimbus JOSE+JWT before 4.39, there is no integer-overflow check when converting length values from bytes to bits, which allows attackers to conduct HMAC bypass attacks by shifting Additional Authenticated Data (AAD) and ciphertext so that different plaintext is obtained for the same HMAC.
Basic information
Type
reviewed
Severity
high Advisory on GitHub
Open advisory ↗ Repository advisory
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Source code
Not specified Published (advisory)
2022-05-13 01:30:32 UTC
Updated
2023-01-29 05:03:43 UTC
GitHub reviewed
2022-11-08 22:28:09 UTC
NVD published
2017-08-20
EPSS Score
Score
Percentile
0.15%
35.08%
CVSS Scores
Base score
Version
Severity
Vector
7.5
3.0
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CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
CWEs
CWE id
Name
CWE-345
Insufficient Verification of Data Authenticity
Affected packages (1)
Vulnerable version ranges and first patched releases as published by GitHub.
Ecosystem
Package
Vulnerable range
First patched
Vulnerable functions
maven
com.nimbusds:nimbus-jose-jwt < 4.39
4.39
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cvelogic
Threat Intelligence