How severe is CVE-2026-1642?

CVE-2026-1642 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-2026-1642 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-1642?

CVE-2026-1642 primarily affects F5 Nginx Gateway Fabric. In total, 17 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-1642?

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

Does CVE-2026-1642 have an EU (EUVD) identifier?

Yes. CVE-2026-1642 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5498.

When was CVE-2026-1642 published?

CVE-2026-1642 was published on 2026-02-04 and last updated on 2026-06-17.

CVE-2026-1642

CVE-2026-1642 is a medium-severity vulnerability in F5 Nginx Gateway Fabric 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-345.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v4: 8.2
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-5498
Weakness: CWE-345
Affected product: F5 Nginx Gateway Fabric
Published: 2026-02-04
Last modified: 2026-06-17

Description

A vulnerability exists in NGINX OSS and NGINX Plus when configured to proxy to upstream Transport Layer Security (TLS) servers. An attacker with a man-in-the-middle (MITM) position on the upstream server side—along with conditions beyond the attacker's control—may be able to inject plain text data into the response from an upstream proxied server. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Frequently asked questions

What is CVE-2026-1642?: A vulnerability exists in NGINX OSS and NGINX Plus when configured to proxy to upstream Transport Layer Security (TLS) servers. An attacker with a man-in-the-middle (MITM) position on the upstream server side—along with conditions beyond the attacker's control—may be able to inject plain text data into the response from an upstream proxied server. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
How severe is CVE-2026-1642?: CVE-2026-1642 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-2026-1642 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-1642?: CVE-2026-1642 primarily affects F5 Nginx Gateway Fabric. In total, 17 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-1642?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-1642 have an EU (EUVD) identifier?: Yes. CVE-2026-1642 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5498.
When was CVE-2026-1642 published?: CVE-2026-1642 was published on 2026-02-04 and last updated on 2026-06-17.

References

Affected products (17)

cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p3:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:p3:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r34:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r34:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r35:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r36:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:*:*:*:*

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