Gogs: DOM-based XSS via Milestone Name on New Issue Page

published 2026-06-23 4 mo ago modified 2026-07-21 3 mo ago also GHSA-vcm5-gvmp-78mp , GO-2026-5661 , EUVD-2026-39075

cvss: 4.8; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits: 0; none known

Gogs is an open source self-hosted Git service. Prior to 0.14.3, in new_form.tmpl, milestone names are rendered with Go's default auto-escaping ({{.Name}}), which converts < to < etc. This prevents direct HTML injection. However, when the browser renders the DOM, the text content of the element contains the decoded original payload. Semantic UI 2.4.2's dropdown component has preserveHTML: true as the default setting. When a user selects a dropdown item, the internal set.text() method calls jQuery's .html() with the item's text content. This re-parses the decoded text as HTML, creating the injected element and triggering the JavaScript event handler. An attacker can store an HTML/JavaScript payload in a milestone name, and when any user opens the New Issue page and interacts with the milestone dropdown, the payload executes in their browser via Semantic UI's preserveHTML behavior. This vulnerability is fixed in 0.14.3.

Patch / fix

fixed in 1 distros 1 links 3

go gogs.io/gogs 0.14.3

govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

github.com/gogs/gogs@573eacd commit
github.com/gogs/gogs#8325 pull request
github.com/gogs/gogs/releases/tag/v0.14.3 release

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 4 mo ago (2026-06-25)

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/gogs/gogs/security/advisories/GHSA-vcm5-gvmp-78mp referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	4.8	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
CNA	4.0	4.8	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/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

Affected packages

ecosystem	package	affected	fixed in
go	gogs.io/gogs	<0.14.3 all versions	0.14.3

Affected products

gogs gogs

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /gogs/gogs/pull/8325
web
github.com /gogs/gogs/commit/573eacdc658641487f8ad883da96b29ec8e2852d
web
github.com /gogs/gogs/security/advisories/GHSA-vcm5-gvmp-78mp
exploit, web, advisory
github.com /gogs/gogs/releases/tag/v0.14.3
web
nvd.nist.gov /vuln/detail/CVE-2026-52807
advisory
github.com /gogs/gogs
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary