CVE-2026-52796
Summary
Special template of issue index pattern may cause panic.
Details
in internal/markup/markup.go
link = fmt.Sprintf(<a href="%s">%s</a>, com.Expand(metas["format"], metas), m)
Issue index pattern is rendered to link with com.Expand.
However, com.Expand is not safe.
i = strings.Index(template, "}")
if s, ok := match[template[:i]]; ok {
when { is found but } not found, i comes to 1, template[:-1] will be called, and then panicked
image
finally, all pages than contains issue index are unavailable.
PoC
1. set issue index pattern as follow
image
2. add a commit which point to an issue in its msg
image
using #1 above
Impact
DoS that cause part of pages of the specify repo unavailable.
⚡ Watch CVE-2026-52796
Get an email if CVE-2026-52796 is added to CISA KEV, gains public exploit code, or a new advisory cites it — max one per day, one-click unsubscribe.
Exploitation outlook
- Low exploitation risk0.23% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 13% of all EPSS-scored CVEs.
Advisory coverage (1)
- lowGHSA-4j89-2c4f-44c6: Gogs has DoS in rendering issue index patternghsa · 2026-06-22
External references
Embed the live status
— this badge updates automatically when the KEV or exploit status changes. How to embed it →
[](https://www.csirts.com/cve/CVE-2026-52796)