CVE-2021-4160BN_mod_exp may produce incorrect results on MIPS
- 5.9MediumCVSS base score
- 3.8%Exploitation in 30 daysEPSS · top 9.9% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
There is a carry propagation bug in the MIPS32 and MIPS64 squaring procedure. Many EC algorithms are affected, including some of the TLS 1.3 default curves. Impact was not analyzed in detail, because the pre-requisites for attack are considered unlikely and include reusing private keys. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH are considered just feasible (although very difficult) because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be significant. However, for an attack on TLS to be meaningful, the server would have to share the DH private key among multiple clients, which is no longer an option since CVE-2016-0701. This issue affects OpenSSL versions 1.0.2, 1.1.1 and 3.0.0. It was addressed in the releases of 1.1.1m and 3.0.1 on the 15th of December 2021. For the 1.0.2 release it is addressed in git commit 6fc1aaaf3 that is available to premium support customers only. It will be made available in 1.0.2zc when it is released. The issue only affects OpenSSL on MIPS platforms. Fixed in OpenSSL 3.0.1 (Affected 3.0.0). Fixed in OpenSSL 1.1.1m (Affected 1.1.1-1.1.1l). Fixed in OpenSSL 1.0.2zc-dev (Affected 1.0.2-1.0.2zb).
Timeline
ID reserved
By openssl
- 36 days later
· 36 days later
Published
- 3 years later
· 3 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 |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 3.8% · top 9.9% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.
Affected products
References
References10
- https://www.openssl.org/news/secadv/20220128.txt (opens in a new tab)x_transferred
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=3bf7b73ea7123045b8f972badc67ed6878e6c37f (opens in a new tab)x_transferred
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=e9e726506cd2a3fd9c0f12daf8cc1fe934c7dddb (opens in a new tab)x_transferred
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=6fc1aaaf303185aa5e483e06bdfae16daa9193a7 (opens in a new tab)x_transferred
- DSA-5103 (opens in a new tab)vendor-advisoryx_transferred
- https://www.oracle.com/security-alerts/cpuapr2022.html (opens in a new tab)x_transferred
- https://www.oracle.com/security-alerts/cpujul2022.html (opens in a new tab)x_transferred
- https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf (opens in a new tab)x_transferred
- GLSA-202210-02 (opens in a new tab)vendor-advisoryx_transferred
- https://security.netapp.com/advisory/ntap-20240621-0006/ (opens in a new tab)x_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-2021-34028 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (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-2021-4160)Record last updated .