CyberSecBulletin
CVE-2026-45447NVD status: Modified

OpenSSL: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-45447 is a high-severity use after free vulnerability in OpenSSL, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 4.0.1, 3.6.3, 3.5.7 as the first without the flaw, so updating OpenSSL to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 4% chance of exploitation within 30 days, which is in the top 9.3% of all scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update OpenSSL to 4.0.1 or 3.6.3 or 3.5.7 or 3.4.6, whichever matches your release line, or a later version.
  2. Read the advisory on openssl-library.org for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
OpenSSLOpenSSL4.0.0 up to, but not including, 4.0.1; 3.6.0 up to, but not including, 3.6.3; 3.5.0 up to, but not including, 3.5.7; 3.4.0 up to, but not including, 3.4.6; 3.0.0 up to, but not including, 3.0.21; 1.1.1 up to, but not including, 1.1.1zh; 1.0.2 up to, but not including, 1.0.2zq4.0.1, 3.6.3, 3.5.7, 3.4.6, 3.0.21, 1.1.1zh
Red HatRed Hat Enterprise Linux 10Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-OnNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update ServiceNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.6 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat OpenShift Container Platform 4.12Not specified in the recordNot stated
Red HatCost Management 4Not specified in the recordNot stated
Red Hatmulticluster engine for Kubernetes 2.8Not specified in the recordNot stated
Red HatRed Hat Advanced Cluster Management for Kubernetes 2.13Not specified in the recordNot stated
Red HatRed Hat Discovery 2Not specified in the recordNot stated
Red HatRed Hat Insights proxy 1.5Not specified in the recordNot stated
Red HatRed Hat Update Infrastructure 5Not specified in the recordNot stated
Red HatMulticluster Engine for KubernetesNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 7Not specified in the recordNot stated
Red HatRed Hat Hardened ImagesNot specified in the recordNot stated
Red HatRed Hat JBoss Core ServicesNot specified in the recordNot stated
Red HatRed Hat JBoss Web Server 6Not specified in the recordNot stated
Red HatRed Hat JBoss Web Server 7Not specified in the recordNot stated

Version data comes from the organisation that assigned the CVE; 1 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighCISA (ADP)
CVSS 3.18.1HighCNA

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in OpenSSL

All OpenSSL vulnerabilities

Recent Use After Free vulnerabilities

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