What is CVE-2026-45447?

CVE-2026-45447 is Heap Use-After-Free in the PKCS7_verify() Function. The supplied enrichment data classifies it as Memory Corruption mapped to CWE-416 Use After Free; CWE-825 CWE-825.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-45447. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-45447 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

2 public PoC repositories reported; 0 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-45447 using CVSS 8.8, EPSS 4%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

highMemory Corruptionpublic exploit

CVE-2026-45447

CVE-2026-45447 — Heap Use-After-Free in the PKCS7_verify() Function

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.

Published Jun 9, 2026Updated Aug 25, 2026Sources: NVD, OpenSSL (CNA), Red Hat (VEX), SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Exploit code

public exploit, none observed

EPSS

ahead of 89% of scored CVEs

Affects

OpenSSL

7 products listed

CVSS base

8.8

high · 2 sources

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade OpenSSL to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

Red Hat VEX · CVE-2026-45447

fixed312affected6not affected352

vendor_fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
OpenSSL	OpenSSL	4.0.0 to < 4.0.1	Vulnerable
OpenSSL	OpenSSL	3.6.0 to < 3.6.3	Vulnerable
OpenSSL	OpenSSL	3.5.0 to < 3.5.7	Vulnerable
OpenSSL	OpenSSL	3.4.0 to < 3.4.6	Vulnerable
OpenSSL	OpenSSL	3.0.0 to < 3.0.21	Vulnerable
OpenSSL	OpenSSL	1.1.1 to < 1.1.1zh	Vulnerable
OpenSSL	OpenSSL	1.0.2 to < 1.0.2zq	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

Low

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
8.8	CVSS 3.1	high	2.8	5.9	CNA
8.1	CVSS 3.1	high	2.2	5.9	CNA, Red Hat (VEX)

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-416 · Use After Free

Modify Memory
DoS: Crash, Exit, or Restart
Execute Unauthorized Code or Commands

Mitigation: Choose a language that provides automatic memory management.

Weakness & attack patterns

CWE-416Use After Free
CWE-825

Inferred from the weakness class — not observed against this CVE.

CAPEC-100 · Overflow BuffersCAPEC-123 · Buffer Manipulation

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

5 more posts on this CVEShowing 5 of 10 · Who is discussing this CVE, and how loudlyUnlock free

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /MIME.
Prioritize edge telemetry for network-reachable OpenSSL.
Monitor for scanner or exploit-pattern traffic after 2 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Groups associated with this CVE

Groups reported in connection with this vulnerability. A reported association, not a confirmed observation of that group using it — and not scoped to any sector or campaign.

hostname2ur.jp57
mitchellKrogza.phishing-General-List · Dec 13, 2024
hostnamequillacollo.gob.bo69
Hole Cert · Aug 26, 2026
ip222.255.200.2067
Rutgers Blacklisted IPs · Nov 24, 2020
ip219.117.201.22675
AbuseIPDB Hourly Update · Aug 28, 2026
hostnamesunucun.com.tr4
SOCRadar Internet Wide-Scanner · Mar 15, 2025

5 more indicators on this CVEShowing 5 of 10 · Hashes, addresses and domains from a live threat exchangeUnlock free

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 8.8 (AV:N)
Aug 25, 2026 · NVD
Initial · CVE published
Jun 9, 2026 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

12×SvrsJun 10, 2026 – Jul 6, 2026 · SOCRadar CTI
6×TweetsJun 10, 2026 – Jul 6, 2026 · SOCRadar CTI
2×Github ReposJun 11, 2026 – Jun 13, 2026 · SOCRadar CTI
1×2 times mentioned on 1 Telegram channelsJun 13, 2026 · SOCRadar CTI

References

28 on the record

github.com/openssl/openssl/commit/3aad5eb7af4de4ee0633c30a8541a54d9bbde63c
Patch, NIST
github.com/openssl/openssl/commit/7d4a980c62258c5910cc883936e0c8dbab4d75a8
Patch, NIST
github.com/openssl/openssl/commit/9dfd688ad2290fc5075cacbc9bf0c9a93eefed54
Patch, NIST
github.com/openssl/openssl/commit/a541ae8bfe849a30cc885e8780715c0f488e496c
Patch, NIST
github.com/openssl/openssl/commit/c505d7559da5d5f9f2c3913c6883a5562ce7273e
Patch, NIST
openssl-library.org/news/secadv/20260609.txt
Vendor Advisory, NIST
access.redhat.com/errata/RHSA-2026:25237
Vendor Advisory, NIST
access.redhat.com/errata/RHSA-2026:25239
Vendor Advisory, NIST

Coverage

8 stories from the feeds we poll

3 more reports on this CVEShowing 5 of 8 · Vendor research and security press coverageUnlock free

Elsewhere on this site

OpenSSLevery CVE for this vendor
Memory Corruptionsame class
CWE-416other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

Only the 5 indicator(s) reported for this CVE are available; no packet-level or host-forensic artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-45447 is Heap Use-After-Free in the PKCS7_verify() Function, a high vulnerability affecting OpenSSL from OpenSSL. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-45447. Public exploit evidence is: 2 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 8.8 describes technical severity, while EPSS 4% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.