Vulnerability in qpdf (DEBIAN-CVE-2021-36978)

Summary

Vulnerability in qpdf (DEBIAN-CVE-2021-36978). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 10.1.0-1 or later.

Original description

The description as published by the source.

QPDF 9.x through 9.1.1 and 10.x through 10.0.4 has a heap-based buffer overflow in Pl_ASCII85Decoder::write (called from Pl_AES_PDF::flush and Pl_AES_PDF::finish) when a certain downstream write fails.

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 DEBIAN-CVE-2021-36978 has been found in qpdf.
Risk of unauthorized operations or information disclosure.
What to do: upgrade qpdf to 10.1.0-1 or later.
If unsure, ask your IT team or search "qpdf DEBIAN-CVE-2021-36978" on the vendor's site.

DEBIAN-CVE-2021-36978 (qpdf)
Attack vector: local / unauthenticated
Patched: 10.1.0-1 — 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 qpdf.

📍 Affected scope

Check the vendor advisory for the affected versions of qpdf.

🔥 Severity

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

🔧 How to fix

Update to 10.1.0-1.

🛡️ 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 'qpdf' . 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 'qpdf' . | 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 qpdf 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 qpdf to 10.1.0-1
```
ステージング環境で 10.1.0-1 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

Debian:12 qpdf

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"10.1.0-1"}]}]

Debian:13 qpdf

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"10.1.0-1"}]}]

Debian:14 qpdf

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"10.1.0-1"}]}]

References

advisory security-tracker.debian.org