# CVE-2020-14968: RSA-PSS signature validation vulnerability by prepending zeros in jsrsasign

> The jsrsasign library fails to validate RSA-PSS signatures, allowing attackers to bypass signature checks or potentially trigger memory corruption.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Jun 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-q3gh-5r98-j4h3

## What is CVE-2020-14968?

CVE-2020-14968 is a critical vulnerability in n/a, published on 22 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in the jsrsasign package before 8.0.17 for Node.js. Its RSASSA-PSS (RSA-PSS) implementation does not detect signature manipulation/modification by prepending '\0' bytes to a signature (it accepts these modified signatures as valid). An attacker can abuse this behavior in an application by creating multiple valid signatures where only one signature should exist. Also, an attacker might prepend these bytes with the goal of triggering memory corruption issues.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2020-14968?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `jsrsasign` | npm | From 3.0.0 | 8.0.17 |
| `jsrsasign` | npm | From 3.0.0 | 8.0.17 |

Products: Kjur Jsrsasign, Netapp Max Data.

## How do I fix CVE-2020-14968?

Upgrade jsrsasign to 8.0.17 or later.

## Is CVE-2020-14968 being exploited?

There is no known exploitation of CVE-2020-14968 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-14967](https://insights.sbomify.com/CVE-2020-14967/): RSA PKCS#1 decryption vulnerability with 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)
- [CVE-2021-30246](https://insights.sbomify.com/CVE-2021-30246/): RSA signature validation vulnerability on maleable encoded message in jsrsasign (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-14968 and fix it if it is affected.

What it is: CVE-2020-14968 is a critical vulnerability in n/a, published on 22 Jun 2020. 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-2020-14968 in the wild and no public exploit code.

Affected packages and fixed versions:
- jsrsasign (npm): affected from 3.0.0; fixed in 8.0.17
- jsrsasign (npm): affected from 3.0.0; fixed in 8.0.17

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-2020-14968/ (Markdown: https://insights.sbomify.com/CVE-2020-14968/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-14968
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-14968
- OSV: https://osv.dev/vulnerability/CVE-2020-14968

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-14968/
Summaries are generated and may contain mistakes; the official description above is the record.