Categories
CVE-2026-69247

Vulnerability in cryptography (CVE-2026-69247)

Summary

Vulnerability in cryptography (CVE-2026-69247). Risk of unauthorized operations or information disclosure. Exploitable via pkcs7_decrypt_der. Mitigation: upgrade to 50.0.0 or later.

Original description

The description as published by the source.

Summary

pkcs7_decrypt_der, pkcs7_decrypt_pem, and pkcs7_decrypt_smime reported the
outcome of decrypting a RecipientInfo's encryptedKey in several
distinguishable ways, one of which disclosed the exact length recovered from the
RSA operation. The same distinction was also observable by timing. An
application that decrypts attacker-supplied EnvelopedData and reflects the
outcome gives the attacker a Bleichenbacher oracle against the
content-encryption key.

Introduced in 44.0.0. Fixed in 50.0.0.

Details

Decryption ran as: RSA PKCS#1 v1.5 decrypt of encryptedKey → build an AES
cipher from the result → AES-CBC decrypt and PKCS#7 unpad. Each stage failed
differently, with no RFC 3218 mitigation:

  1. invalid RSA padding → Decryption failed
  2. valid padding, bad key length → Invalid key size (N) for AES., disclosing N
  3. correct length, wrong key → Invalid padding bytes.
  4. the real key → plaintext

Case 1 is reachable only where the linked library lacks implicit rejection:
OpenSSL 3.0 and 3.1, LibreSSL, and BoringSSL. On OpenSSL 3.2+, used in our wheels,
invalid padding instead returns a synthetic plaintext of
pseudorandom length, so the error channel does not distinguish conforming
ciphertexts.

Exploitation requires a service that auto-decrypts untrusted EnvelopedData
matching the victim certificate and answers adaptively at high volume, such as
an S/MIME gateway or mail filter.

Fix

Per RFC 3218, the content-encryption algorithm is now re…

Source: GitHub Security Advisories (Global) 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-2026-69247 has been found in cryptography.
Attackers can target a specific entry point like pkcs7_decrypt_der over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade cryptography to 50.0.0 or later.
If unsure, ask your IT team or search "cryptography CVE-2026-69247" on the vendor's site.

CVE-2026-69247 (cryptography) — CWE-208
Attack surface: pkcs7_decrypt_der / pkcs7_decrypt_pem / pkcs7_decrypt_smime / RecipientInfo
Patched: 50.0.0 — 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 (CWE-208) exists in cryptography. Attackers reach the vulnerable code path via pkcs7_decrypt_der.

📍 Affected scope

Check the vendor advisory for the affected versions of cryptography. Attack surface: pkcs7_decrypt_der / pkcs7_decrypt_pem / pkcs7_decrypt_smime / RecipientInfo.

🔥 Severity

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

🔧 How to fix

Update to 50.0.0.

🛡️ 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 'cryptography' . 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. 1
    Identify exposure identify
    grep -r 'cryptography' . | 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 cryptography を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch
    Upgrade cryptography to 50.0.0

    ステージング環境で 50.0.0 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。

  3. 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

pip cryptography
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"50.0.0"}]}]
PyPI cryptography
[{"type":"ECOSYSTEM","events":[{"introduced":"44.0.0"},{"fixed":"50.0.0"}]}]

References

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