CVE-2026-6291
6.5 · MEDIUMOverview
CVE-2026-6291 is a medium-severity vulnerability affecting wolfssl wolfssl. It was published on June 25, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
Bleichenbacher padding oracle in PKCS#7 KTRI decryption. When decrypting PKCS#7 EnvelopedData using RSA PKCS#1 v1.5 key transport, wolfSSL returned distinguishable error codes depending on whether RSA padding validation failed versus whether the decrypted content was malformed. An attacker able to submit crafted EnvelopedData messages and observe error responses could use this as a padding oracle to incrementally recover the encrypted Content Encryption Key (CEK). The fix generates a deterministic pseudo-random fake CEK on padding failure (via HMAC-SHA256) and proceeds with decryption identically, using constant-time operations throughout, so that all failure paths produce the same error regardless of padding validity.
Remediation
Check the references section for vendor advisories and patches from wolfssl. Update wolfssl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| wolfssl | wolfssl | >= 3.9.10, < 5.9.2 | Affected |
Frequently Asked Questions
What is CVE-2026-6291?
CVE-2026-6291 is a medium-severity vulnerability affecting wolfssl wolfssl. It was published on June 25, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
How severe is CVE-2026-6291?
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-6291?
Check the references section for vendor advisories and patches from wolfssl. Update wolfssl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-6291?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-6291 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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