OpenSSL PKCS#7 CVE-2026-45447
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.
AI Analysis
Technical Summary
This vulnerability in OpenSSL arises from improper handling of an empty ASN.1 SET in the digestAlgorithms field of SignedData during PKCS#7 signature verification. The incorrect freeing of a caller-owned BIO object during PKCS7_verify() leads to a use-after-free condition. This can cause application crashes, heap corruption, or potentially remote code execution. The issue specifically affects applications using OpenSSL's PKCS#7 APIs; those using CMS APIs or FIPS modules are not vulnerable. OpenSSL has released official fixes to address this vulnerability.
Potential Impact
Exploitation of this vulnerability can result in application crashes or heap corruption, which may be leveraged for remote code execution. The impact is limited to applications that utilize OpenSSL's PKCS#7 APIs for signature verification. Systems using CMS APIs or FIPS modules are not affected. There are no known exploits in the wild at this time.
Mitigation Recommendations
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.
OpenSSL PKCS#7 CVE-2026-45447
Description
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.
Reddit Discussion
Especially relevant on systems processing PKCS#7 or S/MIME contents
Links cited in this discussion
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in OpenSSL arises from improper handling of an empty ASN.1 SET in the digestAlgorithms field of SignedData during PKCS#7 signature verification. The incorrect freeing of a caller-owned BIO object during PKCS7_verify() leads to a use-after-free condition. This can cause application crashes, heap corruption, or potentially remote code execution. The issue specifically affects applications using OpenSSL's PKCS#7 APIs; those using CMS APIs or FIPS modules are not vulnerable. OpenSSL has released official fixes to address this vulnerability.
Potential Impact
Exploitation of this vulnerability can result in application crashes or heap corruption, which may be leveraged for remote code execution. The impact is limited to applications that utilize OpenSSL's PKCS#7 APIs for signature verification. Systems using CMS APIs or FIPS modules are not affected. There are no known exploits in the wild at this time.
Mitigation Recommendations
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.
Technical Details
- Source Type
- Subreddit
- cybersecurity
- Reddit Score
- 0
- Discussion Level
- minimal
- Content Source
- reddit_link_post
- Post Type
- link
- Domain
- null
- Newsworthiness Assessment
- {"score":45,"reasons":["external_link","newsworthy_keywords:cve-","security_identifier","established_author","very_recent"],"isNewsworthy":true,"foundNewsworthy":["cve-"],"foundNonNewsworthy":[]}
- Has External Source
- true
- Trusted Domain
- false
Threat ID: 6a29641fc9170919df1b7aaf
Added to database: 06/10/2026, 13:18:23 UTC
Last enriched: 07/06/2026, 23:32:08 UTC
Last updated: 07/20/2026, 01:05:01 UTC
Views: 489
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.