Vulnerability in curl (ALPINE-CVE-2021-22926)

Summary

Vulnerability in curl (ALPINE-CVE-2021-22926). Risk of unauthorized operations or information disclosure. Exploitable via CURLOPT_SSLCERT. Mitigation: upgrade to 7.67.0-r5 or later.

Original description

The description as published by the source.

libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the CURLOPT_SSLCERT option (--cert with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport, an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file, it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like /tmp), a malicious user can create a file name with the same name as the app wants to use by name, and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.

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 ALPINE-CVE-2021-22926 has been found in curl.
Attackers can target a specific entry point like CURLOPT_SSLCERT over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade curl to 7.67.0-r5 or later.
If unsure, ask your IT team or search "curl ALPINE-CVE-2021-22926" on the vendor's site.

ALPINE-CVE-2021-22926 (curl)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: CURLOPT_SSLCERT
Patched: 7.67.0-r5 — 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 curl. Attackers reach the vulnerable code path via CURLOPT_SSLCERT without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of curl. Attack surface: CURLOPT_SSLCERT.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 7.67.0-r5.

🛡️ 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 'curl' . 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 'curl' . | 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 curl 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 curl to 7.67.0-r5
```
ステージング環境で 7.67.0-r5 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

Alpine:v3.11 curl

[{"type":"ECOSYSTEM","events":[{"introduced":"7.33.0"},{"fixed":"7.67.0-r5"}]}]

References

advisory security.alpinelinux.org