Is stdlib affected by CVE-2026-39823?

Go stdlib is affected in =1.26.0-0 <1.26.3.

Is CVE-2026-39823 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.3%.

medium

CVE-2026-39823

Q: Is CVE-2026-39823 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.3%.

Go · stdlib

Summary

Bypass of meta content URL escaping causes XSS in html/template

Severity: medium
EPSS: 0.3% (p23)
Also known as: BIT-golang-2026-39823, GO-2026-4982
Published: 2026-05-07

References

https://go.dev/issue/78913
https://go.dev/cl/769920
https://groups.google.com/g/golang-announce/c/qcCIEXso47M

Related advisories

CVE-2026-27145 — medium · Go/stdlib
CVE-2026-42504 — medium · Go/stdlib
CVE-2026-42507 — medium · Go/stdlib
CVE-2026-39820 — medium · Go/stdlib
CVE-2026-33814 — medium · Go/stdlib
CVE-2026-39826 — medium · Go/stdlib
CVE-2026-33811 — medium · Go/stdlib
CVE-2026-42499 — medium · Go/stdlib

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.