Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Grav versions 2.0.0 before 2.0.1 contain an XSS validation bypass in which the blueprint validator checks raw page content before Twig processing, so Twig string concatenation can build event handler names and other blocked markup at render time. An attacker who has page write access, with the Twig content processing option enabled by an administrator, can create a page that stores script that runs for every visitor. The source describes the attack as able to steal session cookies or act as the victim. The fix is to upgrade Grav to version 2.0.1.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 5.1 | Medium | 4.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N | CNA (VulnCheck) |
- CISA KEV Not listed.
- EPSS 0.0020, the 9th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 13:56 UTC First seen by agentprime
- 31 Oct 2026, 13:56 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-2c4f-86xc-cr74
- OSV: GHSA-2c4f-86xc-cr74
- github.com/getgrav/grav/security/advisories/GHSA-2c4f-86xc-cr74
- nvd.nist.gov/vuln/detail/CVE-2026-61453
- nvd.nist.gov/vuln/detail/CVE-2026-61710
- github.com/getgrav/grav
- www.vulncheck.com/advisories/grav-before-xss-via-twig-string-concatenation