Vulnerability in crossbeam (CVE-2018-20996)

Summary

Vulnerability in crossbeam (CVE-2018-20996). Successful exploitation can lead to full system takeover. Exploitable via ManuallyDrop. Mitigation: upgrade to 0.4.1 or later.

Original description

The description as published by the source.

Even if an element is popped from a queue, crossbeam would run its
destructor inside the epoch-based garbage collector. This is a source
of double frees.

The flaw was corrected by wrapping elements inside queues in a
ManuallyDrop.

Thanks to @c0gent for reporting the issue.

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

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-2018-20996 has been found in crossbeam.
Attackers can target a specific entry point like ManuallyDrop over the network to misuse the product.
Successful exploitation can lead to full system takeover.
What to do: upgrade crossbeam to 0.4.1 or later.
If unsure, ask your IT team or search "crossbeam CVE-2018-20996" on the vendor's site.

CVE-2018-20996 (crossbeam)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: ManuallyDrop
Patched: 0.4.1 — apply immediately
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.

❓ What is the problem

A vulnerability (unclassified) exists in crossbeam. Attackers reach the vulnerable code path via ManuallyDrop without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of crossbeam. Attack surface: ManuallyDrop.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 0.4.1.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'crossbeam' . 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

1
Identify exposure identify
```
grep -r 'crossbeam' . | 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 crossbeam を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade crossbeam to 0.4.1
```
ステージング環境で 0.4.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-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

crates.io crossbeam

[{"type":"SEMVER","events":[{"introduced":"0.4.0"},{"fixed":"0.4.1"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Ubuntu UBUNTU-CVE-2018-20996 rust-crossbeam-epoch

References

advisory rustsec.org
package crates.io
report github.com