How severe is CVE-2026-93578?

CVE-2026-93578 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-93578 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-93578?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-93578 published?

CVE-2026-93578 was published on 2026-09-18.

CVE-2026-93578

CVE-2026-93578 is a medium-severity vulnerability with a CVSS 3.x base score of 5.9. 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-1035.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1035
Published: 2026-09-18
Last modified: 2026-09-18

Description

A flaw was found in Netty's Online Certificate Status Protocol (OCSP) Client. The client fails to verify the 'id-kp-OCSPSigning' Extended Key Usage (EKU) in OCSP responder certificates. A remote attacker, holding any valid certificate issued by the same Certificate Authority (CA), can exploit this by forging 'GOOD' OCSP responses for revoked certificates. This bypasses certificate revocation checks, allowing applications using Netty's OCSP Client to accept certificates that should have been revoked, leading to an authorization bypass.

Frequently asked questions

What is CVE-2026-93578?: A flaw was found in Netty's Online Certificate Status Protocol (OCSP) Client. The client fails to verify the 'id-kp-OCSPSigning' Extended Key Usage (EKU) in OCSP responder certificates. A remote attacker, holding any valid certificate issued by the same Certificate Authority (CA), can exploit this by forging 'GOOD' OCSP responses for revoked certificates. This bypasses certificate revocation checks, allowing applications using Netty's OCSP Client to accept certificates that should have been revoked, leading to an authorization bypass.
How severe is CVE-2026-93578?: CVE-2026-93578 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-93578 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-93578?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-93578 published?: CVE-2026-93578 was published on 2026-09-18.

References

Other CWE-1035 vulnerabilities

CVE-2026-93565 — High (CVSS 7.5): A flaw was found in Netty RtspDecoder. The `RtspMethods.valueOf()` function incorrectly strips trailing control bytes…
CVE-2026-93564 — High (CVSS 7.5): A flaw was found in Netty. A reference-count leak in the HAProxy PROXY-v2 message decoder allows a remote,…
CVE-2026-93558 — High (CVSS 7.5): A flaw was found in Netty's WebSocketServerExtensionHandler. A remote, unauthenticated attacker can exploit this…
CVE-2026-93560 — High (CVSS 7.5): A flaw was found in the Netty STOMP codec. A remote attacker could send a specially crafted STOMP frame with a…
CVE-2026-93575 — High (CVSS 7.5): A flaw was found in Netty's MqttDecoder. An unauthenticated remote attacker can exploit this vulnerability by sending a…
CVE-2026-93563 — High (CVSS 7.5): A flaw was found in Netty's `SmtpResponseDecoder` component. A remote attacker, acting as a malicious or…

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