Is CVE-2026-42926 in the CISA KEV catalog?

No. CVE-2026-42926 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-42926?

CVE-2026-42926 has a CVSS v3 base score of 5.8 (MEDIUM).

What is the EPSS score for CVE-2026-42926?

CVE-2026-42926 has an EPSS score of 0.34% (26th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-42926?

Upgrade nginx on debian unstable to 1.30.0-4 or later.

CVE & CISA-KEV Catalog

CVE-2026-42926

MEDIUM

5.8

CVSS v3

NVD

Description

When NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CWE-172

How to fix

Remediation Available

nginxDebian

Fixed in:1.30.0-4CVE-2026-42926

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityNone

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Exploit Intelligence

0.34%probability of exploitation in 30 days

26thpercentile

Low risk: more likely to be exploited than 26% of all known CVEs.

References

Vendor Advisory1

my.f5.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-18.