CVE-2020-8244: 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

Q: How do I fix CVE-2020-8244?

bufferlist: upgrade to 1.2.3, 2.2.1, 3.0.1, 4.0.3; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-8244 being exploited?

CVE-2020-8244 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-8244 affect?

CVE-2020-8244 affects bufferlist, debian linux. Severity is medium (CVSS 6.5). 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 c

Q: How urgent is CVE-2020-8244?

Priority 58/100. Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

MEDIUM 6.5REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2020-8244 is a medium-severity flaw (CVSS 6.5) affecting bufferlist, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.1% (top 18%)
CISA exploited list	No
Weakness	CWE-126, CWE-125
Published	2020-08-30
Last modified	2026-06-17

Publisher (CNA): HackerOne · Vendor: bufferlist project · debian

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-08-30 15:15 UTCPublished CVE record published
2026-06-17 03:26 UTCUpdated Record last modified

bufferlist project bufferlist UPGRADE

Affected: < 1.2.3 · >= 2.0.0 and < 2.2.1 · >= 3.0.0 and < 3.0.1 · >= 4.0.0 and < 4.0.3

Fixed in: 1.2.3, 2.2.1, 3.0.1, 4.0.3

Safe to downgrade to: a release before 2.0.0

1. Check installed version

npm ls bufferlist

2. UPGRADE to 1.2.3

npm install bufferlist@">=1.2.3"

3. If no update is available yet, DOWNGRADE to a release before 2.0.0

npm view bufferlist versions npm install bufferlist@"<2.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-8244?

bufferlist: upgrade to 1.2.3, 2.2.1, 3.0.1, 4.0.3; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-8244 being exploited?

CVE-2020-8244 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-8244 affect?

CVE-2020-8244 affects bufferlist, debian linux. Severity is medium (CVSS 6.5). 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 c

How urgent is CVE-2020-8244?

Priority 58/100. Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

References

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