CVE-2026-74878
Per-worker TOTP rate-limit bypass enables distributed brute-force of 2FA
Is CVE-2026-74878 being exploited?
Not confirmed. CVE-2026-74878 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.40% probability of exploitation in the next 30 days.
How severe is CVE-2026-74878?
CVE-2026-74878 is rated Critical with a CVSS score of 9.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-74878?
Yes. A fix has been recorded for CVE-2026-74878. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-74878 affect?
CVE-2026-74878 affects openssl_encrypt <1.4.0, Applications using openssl_encrypt for TOTP, Multi-worker / clustered server deployments. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-74878?
Upgrade to openssl_encrypt 1.4.0+, centralize rate limiting and add IP/account lockouts
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attackers can bypass in-memory rate limits across workers or after restarts to brute-force TOTP, enabling MFA bypass and account takeover.
Immediate action required
- affected< 1.4.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.