How severe is CVE-2026-74878?

CVE-2026-74878 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-74878 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-74878?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-74878 published?

CVE-2026-74878 was published on 2026-08-17.

CVE-2026-74878

CVE-2026-74878 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 9.3
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-770
Published: 2026-08-17
Last modified: 2026-08-17

Description

openssl_encrypt 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.

Frequently asked questions

What is CVE-2026-74878?: openssl_encrypt 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.
How severe is CVE-2026-74878?: CVE-2026-74878 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-74878 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-74878?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-74878 published?: CVE-2026-74878 was published on 2026-08-17.

References

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities

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CVE-2020-37067 — Critical (CVSS 9.8): Filetto 1.0 FTP server contains a denial of service vulnerability in the FEAT command processing that allows attackers…
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CVE-2025-11832 — Critical (CVSS 9.8): Allocation of Resources Without Limits or Throttling vulnerability in Azure Access Technology BLU-IC2, Azure Access…
CVE-2024-44241 — Critical (CVSS 9.8): The issue was addressed with improved bounds checks. This issue is fixed in iOS 18.1 and iPadOS 18.1, macOS Sequoia…

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