Vulnerability in opam (UBUNTU-CVE-2026-41082)

Summary

Vulnerability in opam (UBUNTU-CVE-2026-41082). Data can be tampered with by attackers. Mitigation: upgrade to 2.0.5-1ubuntu1+esm1 or later.

Original description

The description as published by the source.

In OCaml opam before 2.5.1, a .install field containing a destination filepath can use ../ to reach a parent directory.

Source: OSV.dev (Open Source Vulnerabilities) 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 UBUNTU-CVE-2026-41082 has been found in opam.
Data can be tampered with by attackers.
What to do: upgrade opam to 2.0.5-1ubuntu1+esm1 or later.
If unsure, ask your IT team or search "opam UBUNTU-CVE-2026-41082" on the vendor's site.

UBUNTU-CVE-2026-41082 (opam)
Attack vector: local / unauthenticated / no user interaction
Patched: 2.0.5-1ubuntu1+esm1 — 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 opam.

📍 Affected scope

Check the vendor advisory for the affected versions of opam.

🔥 Severity

Severity: ?. Data can be tampered with by attackers.

🔧 How to fix

Update to 2.0.5-1ubuntu1+esm1.

🛡️ 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 'opam' . 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 'opam' . | 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 opam 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 opam to 2.0.5-1ubuntu1+esm1
```
ステージング環境で 2.0.5-1ubuntu1+esm1 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

Ubuntu:16.04:LTS opam

[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]

Ubuntu:18.04:LTS opam

[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]

Ubuntu:Pro:20.04:LTS opam

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.5-1ubuntu1+esm1"}]}]

Ubuntu:22.04:LTS opam

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.2-1+deb12u1build0.22.04.1"}]}]

Ubuntu:Pro:24.04:LTS opam

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.5-1ubuntu0.1~esm2"}]}]

Ubuntu:25.10 opam

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.0-1+deb13u1build0.25.10.1"}]}]

Ubuntu:Pro:26.04:LTS opam

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.0-1ubuntu0.1~esm1"}]}]

References

advisory ubuntu.com
report ubuntu.com
report cve.org
report github.com