# CVE-2018-13863: MongoDB js-bson regular expression denial of service

Source: https://junglewise.ai/threats/cve-2018-13863-mongodb-js-bson-regular-expression-denial-of-service  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2018-09-17. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2018-13863 · Severity: low · CVSS 3 · Published 2018-09-17

js-bson is a JavaScript library used to serialize and deserialize data for MongoDB. A flaw in the Decimal128 number parser allows attackers to cause a denial of service by providing a long malicious string that triggers excessive regex backtracking, consuming CPU and freezing the application.

Technologies: [bson (npm)](https://junglewise.ai/threats/technologies/bson). Vendors: [MongoDB](https://junglewise.ai/threats/vendors/mongodb), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2018-13863 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2018-13863 being exploited in the wild.

**How severe is CVE-2018-13863?** Low severity, with a CVSS score of 3, published 17 September 2018.

**Which products and versions are affected?** MongoDB Js-Bson 0.5.0 to 1.0.4; bson (npm) SEMVER:introduced=0.5.0,fixed=1.0.5.

**Is there a fix for CVE-2018-13863?** Yes. bson (npm): upgrade to 1.0.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2018-13863 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2018-13863?** Check whether you run MongoDB Js-Bson or bson (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- bson (npm): upgrade to 1.0.5 or later

  ```sh
  npm install bson@1.0.5
  ```


## Technical details

The vulnerability is a Regular Expression Denial of Service (ReDoS) in the Decimal128.fromString() function in lib/bson/decimal128.js. When parsing an untrusted input string, a catastrophic backtracking regex allows an attacker to cause exponential CPU consumption by submitting a carefully crafted long string. The vulnerability affects versions 0.5.0 through 1.0.4. An attacker with network access can trigger this by sending a malicious Decimal128 value to any application using affected js-bson versions. The fix, available in version 1.0.5, adds a string length guard that rejects inputs exceeding 7000 characters.

## Affected products

- MongoDB js-bson 0.5.0 to 1.0.4

## Identifiers

- CVE-2018-13863
- GHSA-8462-q7x7-g2x4

## Timeline

- 2018-09-17: disclosed
- 2018-09-17: patched: Fixed in version 1.0.5

## References

- [https://github.com/mongodb/js-bson/commit/bd61c45157c53a1698ff23770160cf4783e9ea4a](https://github.com/mongodb/js-bson/commit/bd61c45157c53a1698ff23770160cf4783e9ea4a)

## Related threats

- [MongoDB js-bson deserialization of untrusted data](https://junglewise.ai/threats/cve-2019-2391-mongodb-js-bson-deserialization-of-untrusted-data)
- [MongoDB bson deserialization of untrusted data](https://junglewise.ai/threats/cve-2020-7610-mongodb-bson-deserialization-of-untrusted-data)