Vulnerability in pypdf (CVE-2026-102998)
Summary
Vulnerability in pypdf (CVE-2026-102998). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.19.0 or later.
Original description
The description as published by the source.
Impact
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires updating form field values with flattening enabled, which triggers appearance stream generation.
Patches
This has been fixed in pypdf==6.19.0.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #4087.
Source: NIST National Vulnerability Database 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-2026-102998 has been found in pypdf.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade pypdf to 6.19.0 or later.
If unsure, ask your IT team or search "pypdf CVE-2026-102998" on the vendor's site.
CVE-2026-102998 (pypdf) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 6.19.0 — apply immediately
Workaround: If you cannot upgrade yet, consider applying the changes from PR #4087.
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-400) exists in pypdf.
Check the vendor advisory for the affected versions of pypdf.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 6.19.0.
Workaround: If you cannot upgrade yet, consider applying the changes from PR #4087.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'pypdf' . 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
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1Identify exposure identify
grep -r 'pypdf' . | 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
pypdfを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
If you cannot upgrade yet, consider applying the changes from PR [#4087](https://github.com/py-pdf/pypdf/pull/4087).パッチが適用されるまでの応急処置として、If you cannot upgrade yet, consider applying the changes from PR #4087. を実施。回避策の副作用 (機能低下) を確認した上で。
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3Apply patch patch
Upgrade pypdf to 6.19.0ステージング環境で 6.19.0 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。
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4Post-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。