MEDIUM

CVE-2026-6291

Wolfssl Wolfssl 2026-06-25 CVSS v3.1

CVSS

6.5

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.

Weakness (CWE)

CWE-208

EPSS Score

0.24%

Probability of exploitation in next 30 days

15.8th percentile

References

https://github.com/wolfSSL/wolfssl/pull/10203 Issue Tracking https://www.wolfssl.com/docs/security-vulnerabilities/ Vendor Advisory

View on dbcve.org

Base CVE data derived from NVD (public domain). Enrichment by dbcve.org (CC-BY-4.0). Fetched via API.

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