Heap-based Buffer OverflowWeakness · CWE-122

CVE-2026-44983

HIGH · 7.3 CVSS v3.1 Published 2026-05-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
78/100
Remediation priority · High
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
smallbitvec is a growable bit-vector for Rust, optimized for size. From 1.0.1 to 2.6.0, an integer overflow in the internal capacity calculation of smallbitvec can lead to an undersized heap allocation, resulting in a heap buffer overflow through safe APIs only. This allows memory corruption without requiring unsafe code from the caller. This vulnerability is fixed in 2.6.1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The smallbitvec Rust library versions 1.0.1 through 2.6.0 contain an integer overflow vulnerability in the internal capacity calculation logic. When computing the required allocation size for the bit-vector, the calculation can overflow, resulting in an undersized heap buffer being allocated. Through the library's safe APIs, this undersized buffer can then be overflown, leading to heap buffer overflow and potential memory corruption.

MitigationUpgrade smallbitvec to version 2.6.1 or later to obtain the patched version. Audit existing code that uses smallbitvec to confirm no exploitation has occurred and test thoroughly after the update.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Locate smallbitvec in your dependency manifest
    Search your project's Cargo.lock file for a [package] entry with name "smallbitvec" and note the version number listed (e.g., version = "x.y.z")
    Affected if The version found is 1.0.1, 1.0.2, 1.0.3, 1.1.0, or any version through 2.6.0 (inclusive)
  2. Confirm smallbitvec as a direct or transitive dependency
    Run 'cargo tree -p smallbitvec' in your project directory to confirm smallbitvec is in your dependency tree and capture its exact version
    Affected if The command shows smallbitvec present at a version within the 1.0.1 through 2.6.0 range
  3. Check Cargo.toml for direct smallbitvec usage
    Inspect your Cargo.toml file (and any workspace member Cargo.toml files) for 'smallbitvec' listed under [dependencies] or [dev-dependencies]
    Affected if smallbitvec is listed as a direct dependency with a version constraint that resolves to 1.0.1 through 2.6.0 (such as "=1.5.0", "^2.0.0", or ">=1.0.0")
  4. Verify the unsafe capacity method is in use
    Search your codebase for calls to methods that trigger capacity calculation, such as with_capacity, or any code that inserts elements where the total count could exceed the integer limit for capacity
    Affected if Your code uses safe Rust APIs from smallbitvec (like push, extend, or with_capacity) and the version is within the affected range, making the integer overflow possible

You are affected if smallbitvec version 1.0.1 through 2.6.0 is present in your dependency tree and you use any capacity-allocating methods from this crate.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade smallbitvec to version 2.6.1 or later to obtain the patched version. Audit existing code that uses smallbitvec to confirm no exploitation has occurred and test thoroughly after the update.

Recommended fix High confidence

smallbitvec version 2.6.1

  1. Update the smallbitvec dependency in your Cargo.toml to version 2.6.1 or later: change smallbitvec = "1.0.1"..="2.6.0" to smallbitvec = "2.6.1" or use a semver compatible constraint like smallbitvec = ">=2.6.1"
  2. Run `cargo update smallbitvec` to fetch the fixed version
  3. Run `cargo build` to rebuild your project with the patched dependency
  4. Run your test suite to verify the application functions correctly after the upgrade
Caveat Minor patch release; unlikely to introduce breaking changes, but review crate release notes if available

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-44983 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-44983 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data