Open source software can be safe to use, but it is not safe by default. It is code written by others, free to inspect and reuse. Its safety depends on which packages you pick, how current you keep them, and whether you watch for new flaws. The label alone tells you nothing.
TL;DR
- Open source is a license and a way of sharing code, not a safety rating.
- Almost every modern app uses it, so avoiding it is rarely realistic.
- The real risks are unknown versions, old packages, and no one watching.
- Scanning and a simple routine handle most of the risk.
- Not every flaw needs action. Context decides.
What does "open source" actually mean?
Definition: Open source software is code whose source is published under a license that lets others read, use, and often change it. The license is about permission. It says nothing about quality or security.
Think of a public recipe. Anyone can read it and cook it. That does not tell you whether the recipe is good, whether it was tested, or whether the author is still around to fix a mistake. Some public recipes are excellent and some are not.
When people ask if open source is "safe," they usually mean something more specific: can I trust the packages my app depends on? That question has an answer, but it is about each package, not about the whole category. Let us walk through the beliefs that cause the most confusion.
Myth 1: "Anyone can read the code, so someone must have found the problems"
Fact: Being readable is not the same as being reviewed. Open code can be checked by anyone, but many small packages are read by almost nobody beyond their author. Whether a package gets careful review depends on how many people use and maintain it, not on the license.
This is why public tools ask practical questions. The OpenSSF Scorecard project, for example, checks signals such as whether a project practices code review before changes are merged and whether it has a security policy. Those checks exist because review is not automatic.
Myth 2: "A popular package must be safe"
Fact: Popular packages get attention, which helps, but they also attract attackers because one flaw reaches many users. Popularity is a reason to expect fast fixes. It is not a reason to skip checking. Your question stays the same: which version am I running, and is it affected?
Myth 3: "If there is no known flaw, there is no flaw"
Fact: A scan can only report flaws that someone has found and published. A package with no listed problems may be clean, or may simply not have been examined closely. That is why the post on what is a known vulnerability stresses the word "known." A clean report means "nothing known today," not "nothing wrong."
Myth 4: "Old and stable means safe"
Fact: Age cuts both ways. A mature package has had time for bugs to be fixed. But a package that is no longer maintained will not get fixes for flaws found later. The OWASP Top 10 names the use of unmaintained third party components as a weakness type, and tells teams to monitor for components that no longer receive security patches. See how to tell if a package is abandoned for a checklist.
Myth 5: "Open source is riskier than software you pay for"
Fact: This is the wrong comparison. Both kinds have flaws. The difference is in how you learn about them and who fixes them. With open source, you often have to watch public sources yourself and apply the fix yourself. The OWASP guidance says as much: continuously inventory your components and monitor sources such as the CVE list and the National Vulnerability Database. With any software, you stay safe by knowing what you run and keeping it current.
Myth 6: "We do not use open source"
Fact: Almost every modern application does, often without realizing it. Your own code sits on top of frameworks, and those frameworks sit on top of many small packages. Most are indirect, chosen by something else you chose. Read why apps have hundreds of dependencies for how that happens. If you have not listed what you use, you cannot say you do not use any.
Myth 7: "Every flaw a scanner finds needs to be fixed right now"
Fact: This one is not about trust but about workload. A scanner lists every known flaw in every package you include, including code your app never calls. The OSV project describes its goal as helping developers identify known dependency vulnerabilities that pose genuine risk to their application and its environment, so they can focus on those that matter and sustainably manage those that do not affect them. That phrase "genuine risk" is the key idea. Context decides: whether the vulnerable code can run, whether the app is exposed, and whether the flaw is being exploited.
The Cybersecurity and Infrastructure Security Agency (CISA) keeps a catalog of vulnerabilities known to be exploited in the wild, and recommends that organizations use it as an input to their prioritization. If a flaw is on that list, treat it as more urgent. For the rest, rank by exposure. See the reachability analysis FAQ.
So how do I use open source safely?
Here is a simple routine. None of it needs to be fancy.
- Know what you use. Keep a list of your packages and their versions, including indirect ones.
- Scan regularly. Compare that list to published flaw data on a schedule.
- Choose packages with care. Before you add one, check that it is maintained.
- Update in small steps. Take fixes as they arrive so you never fall far behind.
- Rank findings by risk. Fix the exposed and exploited ones first.
- Remove what you do not use. OWASP lists removing unused dependencies first in its patch management advice.
- Write it down. A short policy about who owns what keeps the work from slipping.
A worked example with invented numbers
The numbers here are invented to show how the routine plays out.
A small team ships a web app with 15 direct packages and about 140 packages in total. Their first scan shows 50 findings.
- They check each against exposure and find that 12 are in packages used only during testing.
- Another 18 sit in code the app never calls.
- That leaves 20 that matter. They fix 14 with simple upgrades in one week.
- The remaining 6 need larger upgrades. They schedule those with owners and dates.
Result: the team went from "50 scary findings" to "6 planned jobs" without ignoring anything. They also learned that they were already "using open source" in 140 places. The open source was never the problem. The lack of a routine was.
Try it yourself
The demo below shows how reachability analysis cuts the noise in a sample workspace. Click through and look for how a long list of findings narrows to the ones your code can actually reach.
Click through it at your own pace, or open it full screen.
Quick check
Is open source less secure than paid software?
Neither is safe by default. Both have flaws. What differs is how you learn about them and who applies the fix. For open source, you usually need to watch public sources and apply updates yourself.
Should I avoid open source to be safe?
That is rarely realistic, because almost every modern app relies on it, mostly through indirect packages. A better goal is to know what you use and keep it current.
If my scan is clean, am I safe?
You are safe from the flaws that are known today and covered by the scan. New flaws are published every day, so rescan on a schedule.
How can Safeguard help with this?
Safeguard's SBOM and dependency scanning lists what your software contains and checks it against known vulnerabilities. Reachability analysis helps show which flaws your code can actually reach, and zero day discovery helps surface new issues in packages. Policies and gates can enforce your rules, such as blocking a pull request that adds a package with a known serious flaw.
Try the free scan at gold.safeguard.sh/scan. If the terms are new, define SCA is a good start.
Sources
- OWASP Top 10 2021, A06 Vulnerable and Outdated Components (source text on GitHub)
- OpenSSF Scorecard README
- OSV documentation
- CISA Known Exploited Vulnerabilities Catalog
Last reviewed: 19 October 2026.
