CVE-2026-31837

Name: CVE-2026-31837
Creator: NVD / NIST
Published: 2026-03-10T22:16:21.72+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.7/10EPSS 0.28%

Last modified Jun 17, 2026

CVE-2026-31837 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. Istio is an open platform to connect, manage, and secure microservices. Prior to 1.29.1, 1.28.5, and 1.27.8, a user of Istio is impacted if the JWKS resolver becomes unavailable or the fetch fails, exposing hardcoded defaults regardless of use of the RequestAuthentication resource. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

Description

Istio is an open platform to connect, manage, and secure microservices. Prior to 1.29.1, 1.28.5, and 1.27.8, a user of Istio is impacted if the JWKS resolver becomes unavailable or the fetch fails, exposing hardcoded defaults regardless of use of the RequestAuthentication resource. This vulnerability is fixed in 1.29.1, 1.28.5, and 1.27.8.

Metrics

CVSS 3.1

7.5/10

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

CVSS 4.0

8.7/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/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

0.28%

19.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-200

Affected Software

Vendor	Product	Versions
Istio	Istio	< 1.27.8
Istio	Istio	>= 1.28.0, < 1.28.5
Istio	Istio	>= 1.29.0, < 1.29.1

References

https://github.com/istio/istio/security/advisories/GHSA-v75c-crr9-733cVendor Advisory

Timeline

Published: Mar 10, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-31837?

How severe is CVE-2026-31837?

CVE-2026-31837 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.

How do I fix CVE-2026-31837?

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-2026-31837?

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

Scan your code now

Source: NVD / NIST