Vulnerability in smallbitvec (CVE-2026-44983)
Summary
Vulnerability in smallbitvec (CVE-2026-44983). Risk of unauthorized operations or information disclosure. Exploitable via smallbitvec.
Original description
The description as published by the source.
Summary
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.
Details
The issue originates from unchecked arithmetic in the internal helper function responsible for computing the required buffer size:
(cap + bits_per_storage() - 1) / bits_per_storage()
When cap is close to usize::MAX, the addition:
cap + bits_per_storage() - 1
can overflow in release builds and wrap around due to Rust’s default wrapping semantics for integer overflow in optimized builds.
As a result:
buffer_len(cap)may return a value significantly smaller than required.- The backing storage is allocated with insufficient size.
- Internal metadata (logical length/capacity) reflects a much larger size than the actual allocation.
Subsequent safe API calls (e.g., set, push, reserve) rely on this corrupted metadata and perform index computations that assume sufficient backing storage. These operations eventually reach unsafe internal code paths (e.g., pointer arithmetic and unchecked indexing), leading to out-of-bounds memory access.
Summary of the issue:
integer overflow
→ undersized allocation
→ inconsistent metadata (len/cap vs actual buffer)
→ unsafe internal access using corrupted metadata
→ heap buffer overflow (UB)
PoC
PoC 1: Out-of-bounds write via `fr…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44983 has been found in smallbitvec.
Attackers can target a specific entry point like smallbitvec over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.3/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "smallbitvec CVE-2026-44983" on the vendor's site.
CVE-2026-44983 (smallbitvec) — CWE-122 / CVSS v3 7.3
Attack vector: local / unauthenticated / no user interaction
Attack surface: smallbitvec / unsafe / cap / set
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-122) exists in smallbitvec. Attackers reach the vulnerable code path via smallbitvec without authentication.
Check the vendor advisory for the affected versions of smallbitvec. Attack surface: smallbitvec / unsafe / cap / set.
Severity: High (CVSS 7.3/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'smallbitvec' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'smallbitvec' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
smallbitvecを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-44983 rust-smallbitvec
- Ubuntu UBUNTU-CVE-2026-44983 rust-smallbitvec
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com