Security Advisory - Published 2026-06-10 - OpenSSL
OpenSSL June 2026 CVEs: PKCS#7, CMS, ASN.1, QUIC, and OCSP Self-Check
OpenSSL published a large advisory on 2026-06-09. The most urgent item in the monitor is CVE-2026-45447, a PKCS#7 / S/MIME use-after-free that can crash or corrupt applications that verify signed messages through OpenSSL PKCS#7 APIs. Many normal web servers are exposed through their bundled OpenSSL packages, but the highest concern is custom software that parses signed email, uploaded certificates, CMS containers, or QUIC traffic.
What the monitor raised
| CVE | Area | Operator note |
|---|---|---|
| CVE-2026-45447 | PKCS#7 / S/MIME verification | Highest priority. Review apps that process signed messages or PKCS#7 uploads. |
| CVE-2026-7383 | ASN.1 multibyte string conversion | Vendor severity is low, but update supported OpenSSL branches. |
| CVE-2026-34180 | ASN.1 decoder on 64-bit Unix-like systems | Relevant when attacker-supplied DER, X.509, or PKCS#7 data reaches d2i_* APIs. |
| CVE-2026-45445 | AES-OCB via EVP_Cipher() | Custom crypto integrations should review direct EVP_Cipher use. OpenSSL TLS is not affected. |
| CVE-2026-9076 | CMS password-based decryption | Relevant to services that decrypt untrusted CMS or S/MIME-like input. |
| CVE-2026-42764 | OpenSSL QUIC server token handling | Check custom QUIC servers where address validation was disabled. |
| CVE-2026-34183 | OpenSSL QUIC PATH_CHALLENGE handling | Relevant to custom QUIC clients or servers that can receive untrusted packet floods. |
| CVE-2026-42765 | OCSP response checking with partial chains | Applies to custom certificate verification that enables both required flags. |
10-minute self-check
Step 1: Find the OpenSSL version that is actually loaded
openssl version -a
# Debian / Ubuntu
dpkg -l | egrep 'openssl|libssl'
# RHEL / Rocky / AlmaLinux
rpm -qa | egrep '^openssl|^openssl-libs'Package version matters, but long-running services can keep an old libssl loaded until they restart. After patching, restart the affected service rather than only updating the package.
Step 2: Check whether your applications touch the risky APIs
grep -R "PKCS7_verify\\|CMS_decrypt\\|d2i_X509\\|d2i_PKCS7\\|EVP_Cipher\\|SSL_new_listener\\|X509_V_FLAG_OCSP_RESP_CHECK_ALL\\|X509_V_FLAG_PARTIAL_CHAIN" . 2>/dev/null | head -120This search is a triage shortcut for source trees and deployed scripts. It does not prove exposure. It tells you where to inspect code ownership, input source, and whether users can upload or submit cryptographic containers.
Step 3: Inventory public entry points
- Mail gateways, helpdesks, document portals, or compliance systems that process S/MIME or PKCS#7 signed files.
- Certificate upload, certificate inspection, or mTLS enrollment features.
- Services that decrypt CMS files supplied by customers or partners.
- Custom QUIC servers built on OpenSSL 3.5, 3.6, or 4.0.
- Custom QUIC clients or servers that stay reachable by untrusted peers for long sessions.
- Applications that implement their own AES-OCB, OCSP, or certificate-chain handling.
Patch targets from OpenSSL
| Branch | Upgrade target | Note |
|---|---|---|
| OpenSSL 4.0 | 4.0.1 | Current 4.x users should upgrade. |
| OpenSSL 3.6 | 3.6.3 | Includes QUIC and PKCS#7 fixes. |
| OpenSSL 3.5 | 3.5.7 | Includes QUIC and crypto-library fixes. |
| OpenSSL 3.4 | 3.4.6 | Upgrade if still on this branch. |
| OpenSSL 3.0 | 3.0.21 | Common enterprise LTS line. |
| OpenSSL 1.1.1 / 1.0.2 | 1.1.1zh / 1.0.2zq | Premium support lines only; plan migration if you rely on them. |
After patching
# Restart services that link libssl/libcrypto.
sudo systemctl restart nginx apache2 httpd postfix dovecot php-fpm
# Check deleted old library mappings on Linux.
sudo lsof 2>/dev/null | egrep 'libssl|libcrypto' | grep DEL- Restart any custom services that parse certificates, signed mail, PKCS#7, or CMS files.
- Review crash logs around mail ingestion, certificate upload, QUIC listener startup, and CMS decrypt jobs.
- Check containers separately. Host package updates do not patch old OpenSSL inside images.
- Confirm vendor appliances and hosting control panels ship their own OpenSSL copy before marking them clean.
Signals that need a deeper review
- Repeated worker crashes while processing signed email, certificate uploads, or document attachments.
- Unexpected restarts in services that use OpenSSL directly rather than through a web server package.
- Custom QUIC services with address validation disabled.
- Old containers or appliances that still report OpenSSL 3.0, 3.4, 3.5, 3.6, 4.0, 1.1.1, or 1.0.2 without the fixed release.
Ping7 repair path
Ping7 can review OpenSSL package versions, linked services, container images, and logs from applications that process PKCS#7, S/MIME, CMS, certificate uploads, or QUIC traffic. Start from CVE Repair and include the OS, OpenSSL version, affected services, and whether you run custom crypto code.