CVE-2026-74878: openssl_encrypt before 1.4.0 TOTP Rate Limiter Bypass
opensslencrypt versions before 1.4.0 use an in-memory rate limiter for TOTP brute-force protection that is not shared across workers and is lost on server restart. Attackers can distribute authentication attempts across multiple server instances or retry immediately after a restart to bypass rate limiting protections.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
openssl_encryptto a version that resolves this vulnerability.Fixed in 1.4.0 - Compensating control
Ensure the TOTP brute-force rate limiting is shared/persistent across server instances and across restarts (so attackers cannot distribute attempts across workers or retry immediately after a restart to bypass the in-memory limiter).
Event History
Frequently Asked Questions
What is the severity of CVE-2026-74878?
The severity of CVE-2026-74878 is critical with a score of 9.8.
How do I fix CVE-2026-74878?
To fix CVE-2026-74878, upgrade OpenSSL Encrypt to version 1.4.0 or later.
What impact does CVE-2026-74878 have on TOTP authentication?
CVE-2026-74878 allows attackers to bypass TOTP brute-force protection by exploiting the in-memory rate limiter.
Can CVE-2026-74878 be exploited remotely?
Yes, CVE-2026-74878 can be exploited remotely due to its availability vector.
What are the mitigation strategies for CVE-2026-74878?
Mitigation strategies include ensuring the use of a version of OpenSSL Encrypt that is not affected and employing additional rate limiting mechanisms.