Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-45447 is a high-severity Use After Free (CWE-416) vulnerability in Openssl Openssl. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique OS Credential Dumping (T1003); ranked in the top 10% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
A use-after-free vulnerability exists in OpenSSL when processing specially crafted PKCS#7 or S/MIME signed messages containing an empty ASN.1 SET in the SignedData digestAlgorithms field. During PKCS7_verify(), OpenSSL may incorrectly free a caller-owned BIO, leaving a dangling reference that triggers the flaw on subsequent use by the application. The issue affects any software using the PKCS#7 APIs to handle such messages; CMS API users and the FIPS modules in OpenSSL 3.0 through 4.0 are unaffected. The flaw carries a CVSS score of 9.8 and is tracked as CWE-416.
An unauthenticated remote attacker can supply a malicious PKCS#7 or S/MIME message to trigger the condition. Depending on allocator behavior and the calling application's BIO handling, this may produce a process crash, heap corruption, or remote code execution.
The referenced OpenSSL commits (3aad5eb, 7d4a980, 9dfd688, a541ae8, and c505d75) contain the corrective changes. The current EPSS score of 0.0012 indicates low observed exploitation probability.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-35491
Vulnerability Data
Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification. Impact summary: A use-after-free may result in process crashes, heap corruption, or potentially remote code execution. When processing a PKCS#7 or S/MIME…
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signed message, if the SignedData digestAlgorithms field is present as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during PKCS7_verify(). A subsequent use of the BIO by the calling application results in a use-after-free condition. In the common case this occurs when the application later calls BIO_free() on the BIO originally passed to PKCS7_verify(). Depending on allocator behavior and application-specific BIO usage patterns, this may result in a crash or other memory corruption. In some application contexts this may potentially be exploitable for remote code execution. Applications that process PKCS#7 or S/MIME signed messages using OpenSSL PKCS#7 APIs may be affected. Applications using the CMS APIs for this processing are not affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 3 hardening rules · 3 OS baselines
V1.4.3
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover use-after-free bugs through dynamic analysis or fuzzing.
Engineering principles can require memory-safe constructs or languages that structurally avoid introducing use-after-free.
Process isolation confines the blast radius of use-after-free memory corruption to a single execution domain.
Memory protection controls limit exploitation impact by blocking unauthorized code execution from dangling pointers.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Lifecycle management includes secure development and maintenance phases that reduce memory-safety defects.
Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.
Routine patching removes known use-after-free instances after they have been introduced in released software.
Secure SDLC practices directly incorporate memory-safety tooling and reviews that prevent most use-after-free defects.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. blocks CWE-416
RHEL 8 (1 rule)
- V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. blocks CWE-416
RHEL 9 (1 rule)
- V-257794 RHEL 9 must clear memory when it is freed to prevent use-after-free attacks. blocks CWE-416