# CVE-2024-21484: Marvin Attack of RSA and RSAOAEP decryption in jsrsasign

> An attacker can decrypt RSA ciphertexts by exploiting a timing side-channel in the jsrsasign library, requiring access to many encrypted messages.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:L/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Jan 2024
- **Updated:** 21 Oct 2024
- **Also known as:** GHSA-rh63-9qcf-83gf

## What is CVE-2024-21484?

CVE-2024-21484 is a high-severity vulnerability in jsrsasign, published on 22 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Versions of the package jsrsasign before 11.0.0 are vulnerable to Observable Discrepancy via the RSA PKCS1.5 or RSAOAEP decryption process. An attacker can decrypt ciphertexts by exploiting the Marvin security flaw. Exploiting this vulnerability requires the attacker to have access to a large number of ciphertexts encrypted with the same key.

 Workaround 

The vulnerability can be mitigated by finding and replacing RSA and RSAOAEP decryption with another crypto library.

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2024-21484?

2 open source packages ship an affected version, including jsrsasign. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `jsrsasign` | npm | All versions | 11.0.0 |
| `jsrsasign` | npm | All versions | 11.0.0 |

Products: Kjur Jsrsasign.

## How do I fix CVE-2024-21484?

Upgrade jsrsasign to 11.0.0 or later.

## Is CVE-2024-21484 being exploited?

There is no known exploitation of CVE-2024-21484 in the wild and no public exploit code.

## Other vulnerabilities in jsrsasign

- [CVE-2020-14967](https://insights.sbomify.com/CVE-2020-14967/): RSA PKCS#1 decryption vulnerability with prepending zeros in jsrsasign (critical 9.8)
- [CVE-2020-14968](https://insights.sbomify.com/CVE-2020-14968/): RSA-PSS signature validation vulnerability by prepending zeros in jsrsasign (critical 9.8)
- [CVE-2026-4601](https://insights.sbomify.com/CVE-2026-4601/): jsrsasign: Missing cryptographic validation during DSA signing enables private key extraction (critical 9.4)
- [CVE-2026-4599](https://insights.sbomify.com/CVE-2026-4599/): jsrsasign: Incomplete Comparison Allows DSA Private Key Recovery via Biased Nonce Generation (critical 9.3)
- [CVE-2026-4600](https://insights.sbomify.com/CVE-2026-4600/): jsrsasign: DSA signatures or X.509 certificates can be forged via DSA domain-parameter validation in KJUR.crypto.DSA.setPublic (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-21484 and fix it if it is affected.

What it is: CVE-2024-21484 is a high-severity vulnerability in jsrsasign, published on 22 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-21484 in the wild and no public exploit code.

Affected packages and fixed versions:
- jsrsasign (npm): affected all versions; fixed in 11.0.0
- jsrsasign (npm): affected all versions; fixed in 11.0.0

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-2024-21484/ (Markdown: https://insights.sbomify.com/CVE-2024-21484/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21484
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21484
- OSV: https://osv.dev/vulnerability/CVE-2024-21484

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21484/
Summaries are generated and may contain mistakes; the official description above is the record.