# CVE-2020-12402: Information disclosure in Firefox > Electromagnetic side-channel attacks during RSA key generation can recover secret primes, affecting products built on Firefox. - **Severity:** Medium 4.4 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 9 Jul 2020 - **Updated:** 4 Aug 2024 - **Also known as:** ALPINE-CVE-2020-12402, DEBIAN-CVE-2020-12402, GHSA-p7qx-fg8r-mfq9, SUSE-SU-2020:1850-1, UBUNTU-CVE-2020-12402, USN-4417-1, USN-4417-2, openSUSE-SU-2020:0953-1, openSUSE-SU-2020:0955-1 ## What is CVE-2020-12402? CVE-2020-12402 is a medium-severity vulnerability in Debian Debian Linux, published on 9 Jul 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. ### Official 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. Weakness: CWE-203 (Observable Discrepancy) ## Which versions are affected by CVE-2020-12402? It affects 4 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `mozilla-nss` | SUSE:Linux Enterprise High Performance Computing 15-ESPOS | All versions | 3.53.1-3.45.1 | | `mozilla-nss` | SUSE:Linux Enterprise High Performance Computing 15-LTSS | All versions | 3.53.1-3.45.1 | | `mozilla-nss` | SUSE:Linux Enterprise Module for Basesystem 15 SP1 | All versions | 3.53.1-3.45.1 | | `mozilla-nss` | SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 3.53.1-3.45.1 | | `mozilla-nss` | SUSE:Linux Enterprise Module for Server Applications 15 SP1 | All versions | 3.53.1-3.45.1 | | `mozilla-nss` | SUSE:Linux Enterprise Module for Server Applications 15 SP2 | All versions | 3.53.1-3.45.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server 15-LTSS | All versions | 3.53.1-3.45.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server for SAP Applications 15 | All versions | 3.53.1-3.45.1 | | `mozilla-nss` | openSUSE:Leap 15.1 | All versions | 3.53.1-lp151.2.26.1 | | `mozilla-nss` | openSUSE:Leap 15.2 | All versions | 3.53.1-lp152.2.4.1 | Products: Debian Debian Linux, Fedoraproject Fedora, Mozilla Firefox, Opensuse Leap. ## How do I fix CVE-2020-12402? Upgrade to a fixed version. ## Is CVE-2020-12402 being exploited? There is no known exploitation of CVE-2020-12402 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild) - [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild) - [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild) - [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild) - [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-12402 and fix it if it is affected. What it is: CVE-2020-12402 is a medium-severity vulnerability in Debian Debian Linux, published on 9 Jul 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2020-12402 in the wild and no public exploit code. Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2020-12402/ (Markdown: https://insights.sbomify.com/CVE-2020-12402/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-12402 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-12402 - OSV: https://osv.dev/vulnerability/CVE-2020-12402 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-12402/ Summaries are generated and may contain mistakes; the official description above is the record.