CVE-2026-39826: go Improper Encoding — Fix

Description

If a trusted template author were to write a <script> tag containing an empty 'type' attribute or a 'type' attribute with an ASCII whitespace, the execution of the template would incorrectly escape any data passed into the <script> block.

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CVSS v3.1 Score

6.1

MEDIUM

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

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-116 CWE-116

Affected Products

Vendor	Product	Versions
golang	go	< 1.25.10
golang	go	1.26.0 — 1.26.3

References

Advisories & Patches

https://go.dev/cl/771180 https://go.dev/issue/78981 https://pkg.go.dev/vuln/GO-2026-4980

Other References

https://groups.google.com/g/golang-announce/c/qcCIEXso47M

Frequently Asked Questions

What is CVE-2026-39826? +

If a trusted template author were to write a <script> tag containing an empty 'type' attribute or a 'type' attribute with an ASCII whitespace, the execution of the template would incorrectly escape any data passed into the <script> block. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2026-39826? +

CVE-2026-39826 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-39826? +

CVE-2026-39826 affects products from golang, specifically: go. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-39826? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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