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» CVE-2020-8929
A mis-handling of invalid unicode characters in the Java implementation of Tink versions prior to 1.5 allows an attacker to change the ID part of a ciphertext, which result in the creation of a second ciphertext that can decrypt to the same plaintext. This can be a problem with encrypting deterministic AEAD with a single key, and rely on a unique ciphertext-per-plaintext.
NVD Status： Analyzed ，CVE State: published
Threat Intelligence & Risk Assessment for CVE-2020-8929
Conclusion & alert: CVE-2020-8929 is rated Low Risk (34.5/100) : CVSS Medium severity, with low exploitation likelihood (EPSS 0.47%).Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
Exploit prediction scoring system (EPSS) score for CVE-2020-8929
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
#
Date
Old EPSS score
New EPSS score
Delta (New - Old)
1
2026-06-15
0.06%
0.47%
+0.41%
2
2023-03-07
0.89%
0.06%
-0.83%
3
2022-04-01
—
0.89%
—
Full EPSS history
(6 records total)
Common vulnerability scoring system (CVSS) metrics for CVE-2020-8929
CVSS metrics for this CVE.
Base score
Version
Severity
Vector
Exploitability
Impact
Score source
5.3
3.1
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
3.9
1.4
[email protected]
5.3
3.1
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
3.9
1.4
[email protected]
5.0
2.0
MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N
Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
10.0
2.9
[email protected]
Weakness enumeration for CVE-2020-8929
GitHub Security Advisory for CVE-2020-8929
GHSA-g5vf-v6wf-7w2r · Severity: medium · Ecosystem: maven
— Ciphertext Malleability Issue in Tink Java
Affected software / configurations for CVE-2020-8929
Vendor
Product
Version
Raw CPE
google
tink_java
< 1.5.0
cpe:2.3:a:google:tink_java:*:*:*:*:*:*:*:*
References for CVE-2020-8929
cvelogic
Threat Intelligence