CVE-2017-20228: Flat Assembler 1.71.21 contains a stack-based buffer overflow vulnerability that allows local attackers to exe

Q: How do I fix CVE-2017-20228?

flat assembler: upgrade to newer than 1.71.21. Exact commands for each OS are on this page.

Q: Is CVE-2017-20228 being exploited?

CVE-2017-20228 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-2017-20228 affect?

CVE-2017-20228 affects flat assembler. Severity is high (CVSS 8.4). Flat Assembler 1.71.21 contains a stack-based buffer overflow vulnerability that allows local attackers to execute arbitrary code by supplying oversized input to the application. Attackers can craft malicious assembly input exceeding 5895 b

Q: How urgent is CVE-2017-20228?

Priority 38/100. High severity; Public exploit reference

Routine

HIGH 8.4UPGRADE

CVE-2017-20228 is a high-severity flaw (CVSS 8.4) affecting flat assembler. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Flat Assembler 1.71.21 contains a stack-based buffer overflow vulnerability that allows local attackers to execute arbitrary code by supplying oversized input to the application. Attackers can craft malicious assembly input exceeding 5895 bytes to overwrite the instruction pointer and execute return-oriented programming chains for shell command execution.

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.4 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 87%)
CISA exploited list	No
Weakness	CWE-787
Published	2026-03-28
Last modified	2026-06-17

Publisher (CNA): VulnCheck · Vendor: flatassembler

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

Am I affected?

Timeline

2026-03-28 12:16 UTCPublished CVE record published
2026-06-17 01:15 UTCUpdated Record last modified

flatassembler flat assembler UPGRADE

Affected: <= 1.71.21

Fixed in: newer than 1.71.21

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy flat-assembler || rpm -q flat-assembler || flat-assembler --version

2. UPGRADE to newer than 1.71.21 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade flat-assembler

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade flat-assembler

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2017-20228?

flat assembler: upgrade to newer than 1.71.21. Exact commands for each OS are on this page.

Is CVE-2017-20228 being exploited?

CVE-2017-20228 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-2017-20228 affect?

CVE-2017-20228 affects flat assembler. Severity is high (CVSS 8.4). Flat Assembler 1.71.21 contains a stack-based buffer overflow vulnerability that allows local attackers to execute arbitrary code by supplying oversized input to the application. Attackers can craft malicious assembly input exceeding 5895 b

How urgent is CVE-2017-20228?

Priority 38/100. High severity; Public exploit reference

References

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