Description

Decoding a paletted BMP file with an out-of-range palette index results in a panic when accessing pixels in the invalid image.

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CVSS v3.1 Score

5.3

MEDIUM

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

EPSS — Exploit Prediction

0.0038

Probability of exploitation

0.30%

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.

References

Other References

https://go.dev/cl/781500 https://go.dev/issue/79576 https://groups.google.com/g/golang-announce/c/uhYX90BlBvI https://pkg.go.dev/vuln/GO-2026-5031

Frequently Asked Questions

What is CVE-2026-42500? +

Decoding a paletted BMP file with an out-of-range palette index results in a panic when accessing pixels in the invalid image. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-42500? +

CVE-2026-42500 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0038, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-42500? +

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.