They can. A pin keeps a version fixed, including a version that later turns out to be vulnerable, so pinning without an update process trades surprise changes for slow exposure. The fix is not looser pins. It is a routine that moves pins deliberately and quickly when a fix matters.
What pinning actually buys
Lock files and exact versions give repeatability. The Cargo Book says its lockfile gives deterministic builds across times and machines, and that this helps CI fail only because of new commits, not external factors. The pip documentation requires exact pins for hash-checking so a new release cannot cause a surprise mismatch.
Those are real benefits. They are also a statement about the present: the pin freezes whatever you chose, good or bad.
Cargo's own FAQ is direct about the cost. It warns that determinism can give a false sense of security, and the install documentation says that using the locked option means you will not receive any fixes or updates to any dependency.
Two failure modes
| Approach | Failure |
|---|---|
| Loose ranges, no lock | Unreviewed new releases enter builds, including bad ones |
| Tight pins, no process | Fixed, known vulnerable versions stay in production |
Both are process failures. The first has no gate on change. The second has no trigger for change.
A routine that avoids both
- Pin and lock everything you ship, so a build is a record.
- Scan the locked set on a schedule and on every pull request, so you learn about new advisories for versions you already run.
- Set a time target for each severity band, decided in advance, instead of arguing case by case.
- Update routinely in small batches. Smaller diffs are easier to review and revert.
- Keep a fast path for an urgent fix: a single package bump, tests, review and release without waiting for the next batch.
- Track exceptions. A package held back needs an owner, a reason and a review date.
Using reachability to prioritize
Not every finding is equally urgent. Whether the vulnerable code can be reached from your application changes the priority. It does not remove the finding or the need to update, but it helps sequence the work when many pins are behind.
Remediation that respects review
Automated pull requests can carry the routine work. Whatever tool opens them, keep the same gates: tests run, a human reviews, and the lock file diff is read. An update that merges itself has the same weakness as an unpinned range, only with a nicer log.
Metrics worth watching
- Age of the oldest pinned version in each production service.
- Number of known vulnerable versions in the locked set.
- Time from advisory to fix in production.
- Number of overrides and held-back packages.
These tell you whether pinning has become stability or stagnation.
Where Safeguard fits
Safeguard's continuous dependency scanning and reachability analysis help you see which pinned versions are affected and which findings matter, and autonomous remediation can open fix pull requests. It is off by default, with every category on Manual, so a person approves each change. A free scan is at gold.safeguard.sh/scan.
Try it yourself
Open the demo and see how a pinned version with an available fix is surfaced for a deliberate update.
Click through it at your own pace, or open it full screen.
Quick check
Is pinning bad for security?
No. It makes builds repeatable and gives changes a review point. It becomes a problem only when nothing triggers an update.
How often should pins be updated?
Often enough that no pinned version is far behind, plus an immediate path for urgent fixes. Set the cadence and severity targets in advance.
Sources
Last reviewed: 19 October 2026.
