CVE-2021-4160: 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 c...

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).

Metrics

CVSS 3.1

5.9/10

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

EPSS Probability

3.80%

88.6th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Openssl	Openssl	>= 1.0.2, <= 1.0.2zb
Openssl	Openssl	>= 1.1.1, < 1.1.1m
Openssl	Openssl	3.0.0
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0
Oracle	Health Sciences Inform Publisher	6.2.1.1
Oracle	Health Sciences Inform Publisher	6.3.1.1
Oracle	Jd Edwards Enterpriseone Tools	9.2.6.3
Oracle	Jd Edwards World Security	a9.4
Oracle	Peoplesoft Enterprise Peopletools	8.58
Oracle	Peoplesoft Enterprise Peopletools	8.59
Siemens	Sinec Ins	< 1.0
Siemens	Sinec Ins	1.0
Oracle	Enterprise Manager Ops Center	12.4.0.0

References

https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdfThird Party Advisory
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=3bf7b73ea7123045b8f972badc67ed6878e6c37f
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=6fc1aaaf303185aa5e483e06bdfae16daa9193a7
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=e9e726506cd2a3fd9c0f12daf8cc1fe934c7dddb
https://security.gentoo.org/glsa/202210-02Third Party Advisory
https://security.netapp.com/advisory/ntap-20240621-0006/
https://www.debian.org/security/2022/dsa-5103Third Party Advisory
https://www.openssl.org/news/secadv/20220128.txtVendor Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.htmlThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdfThird Party Advisory
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=3bf7b73ea7123045b8f972badc67ed6878e6c37f
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=6fc1aaaf303185aa5e483e06bdfae16daa9193a7
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=e9e726506cd2a3fd9c0f12daf8cc1fe934c7dddb
https://security.gentoo.org/glsa/202210-02Third Party Advisory
https://security.netapp.com/advisory/ntap-20240621-0006/
https://www.debian.org/security/2022/dsa-5103Third Party Advisory
https://www.openssl.org/news/secadv/20220128.txtVendor Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.htmlThird Party Advisory

Timeline

Published: Jan 28, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-4160?

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).

How severe is CVE-2021-4160?

CVE-2021-4160 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 3.80% probability of exploitation in the next 30 days.

How do I fix CVE-2021-4160?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.