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CVE-2026-1642

HIGHCVSS 8.2/10EPSS 0.34%

Last modified

CVE-2026-1642 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. 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.. EPSS estimates a 0.34% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
5.9/10

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

CVSS 4.0
8.2/10

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.34%

25.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
F5Nginx Gateway Fabric>= 1.2.0, <= 1.6.2—
F5Nginx Gateway Fabric>= 2.0.0, < 2.4.1—
F5Nginx Ingress Controller>= 3.4.0, <= 3.7.2—
F5Nginx Ingress Controller>= 4.0.0, <= 4.0.1—
F5Nginx Ingress Controller>= 5.0.0, < 5.3.3—
F5Nginx Instance Manager>= 2.15.1, <= 2.21.0—
F5Nginx Open Source>= 1.3.0, < 1.28.2—
F5Nginx Open Source>= 1.29.0, < 1.29.5—
F5Nginx Plus>= r33, < r35—
F5Nginx Plusr32—
F5Nginx Plusr33P1
F5Nginx Plusr34P1
F5Nginx Plusr35—
F5Nginx Plusr36—

References

Timeline

Published
Last Modified
Status
Analyzed

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 score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.34% probability of exploitation in the next 30 days.
How do I fix CVE-2026-1642?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-1642?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST