SECUFOCUSNOW
Home›CVE index›CVE-2026-31790
Review reviewHigh

CVE-2026-31790

OpenSSL OpenSSL, SIMATIC CN 4100, openssl

Issue summary: Applications using RSASVE key encapsulation to establish a secret encryption key can send contents of an uninitialized memory buffer to a malicious peer. Impact summary: The uninitialized buffer might contain sensitive data from the previous execution of the application process which leads to sensitive data leakage to an attacker. RSA_public_encrypt() returns the number of bytes written on success and -1 on error. The affected code tests only whether the return value is non-zero. As a result, if RSA encryption fails, encapsulation can still return success to the caller, set t...

CVSS
7.5
EPSS
1.20%
65.2% percentile
CISA KEV
Not listed
Published
2026.04.08
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability1.20%
Technical severityCVSS 7.5

Vulnerability overview

Issue summary: Applications using RSASVE key encapsulation to establish a secret encryption key can send contents of an uninitialized memory buffer to a malicious peer. Impact summary: The uninitialized buffer might contain sensitive data from the previous execution of the application process which leads to sensitive data leakage to an attacker. RSA_public_encrypt() returns the number of bytes written on success and -1 on error. The affected code tests only whether the return value is non-zero. As a result, if RSA encryption fails, encapsulation can still return success to the caller, set t...

Affected product and versions

Product
OpenSSL OpenSSL, SIMATIC CN 4100, openssl
Affected versions
>= 3.6.0 < 3.6.2, >= 3.5.0 < 3.5.6, >= 3.4.0 < 3.4.5, >= 3.3.0 < 3.3.7, >= 3.0.0 < 3.0.20, < V5.0
Fixed versions
3.0.20, 3.3.7, 3.4.5, 3.5.6, 3.6.2

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that OpenSSL OpenSSL, SIMATIC CN 4100, openssl and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE
CWE-754