Is CVE-2026-6291 actively exploited?

No active exploitation of CVE-2026-6291 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-6291 be exploited remotely?

Yes. CVE-2026-6291 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-6291?

CVE-2026-6291 has a CVSS score of 6.5 (MEDIUM).

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MEDIUM

CVE-2026-6291

CWE-208Published: June 25, 2026· Updated: Jun 26, 2026

6.5

CVSS v3.1

EPSS:0.15%probability of exploitation in 30 daysPercentile:4.8th

Official 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.

NVD Source

Technical Analysis

CVE-2026-6291 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 6.5.