CVE-2026-45447VulnerabilityPublished 10 Jun 2026

OpenSSL PKCS#7 CVE-2026-45447

Source Reddit Cybersecurity

Not known to be exploited · fixed in 3.6.3 : update affected systems when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 4.0% chance of exploitation in 30 days – higher than 90% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.6.3, 3.5.7, 3.4.6 +1

Exploitation evidence

Disclosed: evidence found.
Public on cve.org; its publication date is not in this record
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

OpenSSL has issued official fixes for this vulnerability in multiple versions. Users should upgrade to fixed versions to remediate the issue. The affected versions are: >=3.0.0 <3.0.21, >=3.4.0 <3.4.6, >=3.5.0 <3.5.7, >=3.6.0 <3.6.3, and =4.0.0. Applying these updates will mitigate the vulnerability. No additional mitigations are specified by the vendor.

Discussion

CVE-2026-45447 is a use-after-free vulnerability in OpenSSL's PKCS#7 signature verification that occurs when processing specially crafted PKCS#7 or S/MIME signed messages containing an empty ASN.1 SET in the SignedData digestAlgorithms field. This flaw causes OpenSSL to incorrectly free a caller-owned BIO during PKCS7_verify(), potentially leading to crashes, heap corruption, or remote code execution. Applications using OpenSSL PKCS#7 APIs are affected, while those using CMS APIs or FIPS modules are not impacted. The vulnerability has been addressed by OpenSSL in official commits.

r/cybersecurity (opens in a new tab)u/Nerothank0 points0 comments

Especially relevant on systems processing PKCS#7 or S/MIME contents

https://nvd.nist.gov/vuln/detail/CVE-2026-45447

Links cited in the discussion

https://nvd.nist.gov/vuln/detail/CVE-2026-45447

References

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