# CVE-2020-8244: Remote Memory Exposure in bl

> An attacker can trigger a buffer over-read in the bl library to expose uninitialized memory, potentially leaking sensitive data.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Aug 2020
- **Updated:** 4 Aug 2024
- **Also known as:** CLSA-2026-1772756021, CLSA-2026-1774225189, CLSA-2026-1776731791, CLSA-2026-1792491634, DEBIAN-CVE-2020-8244, DLA-2698-1, GHSA-pp7h-53gx-mx7r, UBUNTU-CVE-2020-8244, USN-5098-1, USN-5159-1

## What is CVE-2020-8244?

CVE-2020-8244 is a medium-severity vulnerability in Debian Debian Linux, published on 30 Aug 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A buffer over-read vulnerability exists in bl <4.0.3, <3.0.1, <2.2.1, and <1.2.3 which could allow an attacker to supply user input (even typed) that if it ends up in consume() argument and can become negative, the BufferList state can be corrupted, tricking it into exposing uninitialized memory via regular .slice() calls.

Weakness: CWE-125 (Out-of-bounds Read), CWE-126 (Buffer Over-read)

## Which versions are affected by CVE-2020-8244?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `bl` | npm | All versions | 1.2.3 |
| `bl` | npm | All versions | 1.2.3 |
| `bl` | npm | From 2.0.0 | 2.2.1 |
| `bl` | npm | From 2.0.0 | 2.2.1 |
| `bl` | npm | From 3.0.0 | 3.0.1 |
| `bl` | npm | From 3.0.0 | 3.0.1 |
| `bl` | npm | From 4.0.0 | 4.0.3 |
| `bl` | npm | From 4.0.0 | 4.0.3 |

Products: Bufferlist Project Bufferlist, Debian Debian Linux.

## How do I fix CVE-2020-8244?

Upgrade bl to a fixed version for your release line: 1.2.3, 2.2.1, 3.0.1 or 4.0.3.

## Is CVE-2020-8244 being exploited?

There is no known exploitation of CVE-2020-8244 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8244 and fix it if it is affected.

What it is: CVE-2020-8244 is a medium-severity vulnerability in Debian Debian Linux, published on 30 Aug 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-2020-8244 in the wild and no public exploit code.

Affected packages and fixed versions:
- bl (npm): affected all versions; fixed in 1.2.3
- bl (npm): affected all versions; fixed in 1.2.3
- bl (npm): affected from 2.0.0; fixed in 2.2.1
- bl (npm): affected from 2.0.0; fixed in 2.2.1
- bl (npm): affected from 3.0.0; fixed in 3.0.1
- bl (npm): affected from 3.0.0; fixed in 3.0.1
- bl (npm): affected from 4.0.0; fixed in 4.0.3
- bl (npm): affected from 4.0.0; fixed in 4.0.3

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-2020-8244/ (Markdown: https://insights.sbomify.com/CVE-2020-8244/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8244
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8244
- OSV: https://osv.dev/vulnerability/CVE-2020-8244

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8244/
Summaries are generated and may contain mistakes; the official description above is the record.