cbcvebase.
CVE-2026-45447
published 2026-06-09

CVE-2026-45447: 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…

PriorityP263high8.8CVSS 3.1
AVNACLPRLUINSUCHIHAH
EPSS
2.72%
84.2th percentile
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 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.

Affected

11 ranges
VendorProductVersion rangeFixed in
opensslopenssl
opensslopenssl
opensslopenssl>= 1.0.2 < 1.0.2zq1.0.2zq
opensslopenssl>= 1.1.1 < 1.1.1zh1.1.1zh
opensslopenssl>= 3.0.0 < 3.0.213.0.21
opensslopenssl>= 3.4.0 < 3.4.63.4.6
opensslopenssl>= 3.5.0 < 3.5.73.5.7
opensslopenssl>= 3.6.0 < 3.6.33.6.3
opensslopenssl>= 4.0.0 < 4.0.14.0.1
ubuntuopenssl
ubuntuopenssl1.0

Detection & IOCsextracted from sources · hover to see the quote

  • Trigger condition: a PKCS#7 or S/MIME signed message with the SignedData digestAlgorithms field present as an empty ASN.1 SET causes OpenSSL to incorrectly free a caller-owned BIO inside PKCS7_verify(), leading to a use-after-free.
  • The use-after-free is most commonly observable when the calling application subsequently calls BIO_free() on the BIO originally passed to PKCS7_verify(); monitor for double-free / heap corruption crashes in processes that handle PKCS#7 or S/MIME messages.
  • Only applications using the OpenSSL PKCS#7 APIs (PKCS7_verify()) are affected; applications using the CMS APIs are NOT affected — scope detection/triage accordingly.
  • OpenSSL versions 4.0, 3.6, 3.5, 3.4, 3.0, 1.1.1, and 1.0.2 are all vulnerable; use version detection to identify unpatched instances in the environment.
  • FIPS module builds (OpenSSL 4.0, 3.6, 3.5, 3.4, 3.0) are NOT affected because the vulnerable code is outside the FIPS module boundary — exclude these from alerts to reduce false positives.
  • ·Fixed versions are: OpenSSL 4.0.1, 3.6.3, 3.5.7, 3.4.6, 3.0.21, 1.1.1zh (premium), 1.0.2zq (premium). Verify deployed version against these thresholds when writing version-based detection rules.

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vendor_redhat8.8HIGH
vendor_ubuntu7.5HIGH
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