CVE-2020-8929Ciphertext integrity weakness in Tink
- 5.3MediumCVSS base score
- 0.46%Exploitation in 30 daysEPSS · top 59% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Google
- 8 months later
· 8 months later
Published
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GoogleCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.46% · top 59% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Affected products
- affected stable – < 1.5
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavencom.google.crypto.tink:tinkGHSA-g5vf-v6wf-7w2r (opens in a new tab)
References
References2
- https://github.com/google/tink/commit/93d839a5865b9d950dffdc9d0bc99b71280a8899 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/google/tink/security/advisories/GHSA-g5vf-v6wf-7w2r (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2020-0220 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-g5vf-v6wf-7w2r (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2020-8929)Record last updated .