OpenSSL fixes high-severity PKCS#7 use-after-free and broad library flaws
OpenSSL disclosed a broad set of vulnerabilities affecting ASN.1 parsing, PKCS#12, CMS/PKCS#7, QUIC, OCSP, CMP/CRMF, DH key validation, AEAD cipher handling, and certificate and email validation across the 4.0, 3.6, 3.5, 3.4, and 3.0 branches. The most severe issue, CVE-2026-45447, is a high-severity heap use-after-free in PKCS7_verify() that can be triggered by specially crafted PKCS#7 or S/MIME signed messages and could lead to crashes, heap corruption, or potentially remote code execution.
The advisory also details moderate-severity flaws that could enable forged CMS AuthEnvelopedData messages, denial-of-service conditions in QUIC and OCSP processing, a TLS client double-free via OCSP stapling, a QUIC server NULL dereference, and cryptographic failures in AES-OCB when applications use the EVP_Cipher() one-shot API, alongside numerous lower-severity parsing, validation, and bounds-checking bugs. OpenSSL said most issues were fixed in 4.0.1, 3.6.3, 3.5.7, 3.4.6, and 3.0.21, with 1.1.1zh and 1.0.2zq issued for supported legacy customers; most flaws were reported as outside the OpenSSL FIPS module boundary, except CVE-2026-42770, which affects FIPS modules in multiple supported branches.
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How this story unfolded
2 events from the most recent confirmed update back to the earliest known activity.
OpenSSL releases patched versions for affected branches
The advisory states that fixes were made available in OpenSSL 4.0.1, 3.6.3, 3.5.7, 3.4.6, and 3.0.21, with 1.1.1zh and 1.0.2zq also provided for older premium-support branches where applicable. OpenSSL recommended upgrading to these versions to address the disclosed flaws.
OpenSSL discloses multiple vulnerabilities in security advisory
On 2026-06-09, OpenSSL published a security advisory covering numerous vulnerabilities across PKCS#7, CMS, QUIC, OCSP, ASN.1, PKCS#12, CMP/CRMF, DH key validation, AEAD cipher handling, and certificate/email validation. The most severe issue disclosed was CVE-2026-45447, a high-severity heap use-after-free in PKCS7_verify() that could lead to crashes, heap corruption, or potentially remote code execution.
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Critical OpenSSL Vulnerabilities Enables Remote Code Execution Attacks
cybersecuritynews.com
Open sourceOpenSSL Security Patches Fix Remote Code Execution Risk
securityonline.info
Open source[no-title]
openssl-library.org
Open sourceVulnerabilities 4.0 | OpenSSL Library
openssl-library.org
Open sourceCVE-2026-7383 - Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion
cvefeed.io
Open source[no-title]
freebsd.org
Open sourceoss-sec: OpenSSL Security Advisory
seclists.org
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OpenSSL fixes seven flaws including RSA KEM memory disclosure bug
OpenSSL released fixes for seven vulnerabilities across multiple supported branches, led by **CVE-2026-31790**, a Moderate-severity flaw in RSA KEM `RSASVE` encapsulation that can leak stale or uninitialized memory to a malicious peer. The issue can be triggered when applications process attacker-supplied invalid RSA public keys without validating them first. The advisory also disclosed six Low-severity bugs: an AVX-512/VAES-specific out-of-bounds read in AES-CFB-128, a potential use-after-free or double-free in DANE client code, two CMS-related NULL pointer dereferences, a delta CRL NULL dereference, and a heap buffer overflow in hexadecimal conversion on 32-bit platforms. The project advised users to upgrade to fixed releases **3.0.20**, **3.3.7**, **3.4.5**, **3.5.6**, and **3.6.2**, with premium-support fixes available for **1.1.1zg** and **1.0.2zp** where applicable. OpenSSL said branches **3.1** and **3.2** are out of support and were not analyzed, leaving organizations running those versions without reviewed fixes in this advisory.
May 25, 2026
OpenSSL January Security Update Fixes CMS and PKCS#12 Stack Overflows With RCE Risk
**OpenSSL released a security update on January 27, 2026**, addressing **12 vulnerabilities** across supported branches, including **one High-severity issue with potential remote code execution (RCE)**, one Moderate, and multiple Low-severity flaws. The most serious vulnerability, **CVE-2025-15467 (High)**, is a **pre-authentication stack buffer overflow** in **CMS `AuthEnvelopedData` parsing** when using AEAD ciphers (e.g., **AES-GCM**); a crafted CMS message with an **oversized IV in ASN.1 parameters** can trigger a crash and may enable code execution in applications that parse **untrusted CMS/PKCS#7 content** (notably **S/MIME** workflows). Both sources emphasize that while **DoS is the most likely outcome in many environments**, the presence of a stack write primitive makes the issue operationally significant where untrusted CMS is processed. A second notable issue, **CVE-2025-11187 (Moderate)**, involves a **stack overflow during PKCS#12 MAC verification** (PBMAC1/PBKDF2-related validation), where attacker-controlled parameters (e.g., key length) can lead to crashes and potentially more severe impact when processing **untrusted PKCS#12 files** (e.g., certificate import/export, PKI/CA tooling). Affected versions called out include **OpenSSL 3.x** (with additional low-severity issues spanning older branches such as **1.0.2 and 1.1.1**), and patched releases include **3.6.1, 3.5.5, 3.4.4, 3.3.6, and 3.0.19** (with corresponding fixes for older maintained lines). Datadog notes **OpenSSL 3.x FIPS modules are not affected** by the highlighted CMS and PKCS#12 overflow issues, and both sources point to higher risk in services that ingest these formats from external or user-supplied inputs (e.g., S/MIME gateways, certificate management services).
Mar 21, 2026
OpenSSL Releases Patch Multiple CVEs Across Supported Branches
The OpenSSL Project released updated versions across multiple supported branches to fix a set of security flaws in the SSL/TLS toolkit, with **OpenSSL 3.6.2** carrying the broadest set of patches. The updates address issues including incorrect failure handling in RSA KEM `RSASVE` encapsulation, an out-of-bounds read in `AES-CFB-128` on x86-64 systems with `AVX-512` support, a potential use-after-free in DANE client code, several `NULL` pointer dereference bugs, and a heap buffer overflow in hexadecimal conversion. OpenSSL said the most severe issue in the release was rated **Moderate**. Additional releases — **3.5.6, 3.4.5, 3.3.7, 3.0.20, 1.1.1zg, and 1.0.2zp** — also shipped with security fixes and minor bug corrections, though older branches received smaller subsets of the patches. The 3.6.2 release also repaired two regressions introduced in 3.6.0 affecting `X509_V_FLAG_CRL_CHECK_ALL` behavior and stapled OCSP response handling that could trigger handshake failures. Administrators running **OpenSSL 3.6.x** on x86-64 systems with `AVX-512` enabled were specifically urged to prioritize the `AES-CFB-128` fix because of memory-read exposure.
May 7, 2026