---
title: "CVE-2026-75828: Grav: detectXss() misses an event-handler attribute after an unpaired quote in an unquoted attribute value, giving stored XSS"
url: https://erroneo.us/security/cve/CVE-2026-75828/
description: "CVE-2026-75828 (getgrav/grav (Composer (PHP))): Grav before 2.0.15 contains a stored cross-site scripting vulnerability in the detectXss() function where…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-18
date_modified: 2026-10-08
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-75828"
kev: false
cvss: 9.3
epss: 0.00389
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-75828: Grav: detectXss() misses an event-handler attribute after an unpaired quote in an unquoted attribute value, giving stored XSS

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.4% , percentile 32: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 32% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes getgrav/grav (Composer (PHP)) <= 2.0.14, fixed in 2.0.15 . Check your lockfile, including transitive dependencies.

## What it is

Grav before 2.0.15 contains a stored cross-site scripting vulnerability in the detectXss() function where unpaired quotes in unquoted attribute values bypass event-handler detection. Authenticated editors can inject event handlers like onerror= that pass validation and execute in visitor browsers when page content is rendered.

## Affected packages

- Composer (PHP) `getgrav/grav` <= 2.0.14 → fixed: 2.0.15

## Affected products (CVE record)

- getgrav grav: < 2.0.15

## Severity

- VulnCheck CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N`
- VulnCheck CVSS 3.1: 8.7 `CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.39% probability of exploitation activity in the next 30 days; percentile 32.

## Sources

- [GitHub Security Advisory (GHSA-vfmf-q6x9-cw96)](https://github.com/getgrav/grav/security/advisories/GHSA-vfmf-q6x9-cw96)
- [GitHub Advisory GHSA-vfmf-q6x9-cw96](https://github.com/advisories/GHSA-vfmf-q6x9-cw96)
- [CVE.org record CVE-2026-75828](https://www.cve.org/CVERecord?id=CVE-2026-75828)
- [NVD entry CVE-2026-75828](https://nvd.nist.gov/vuln/detail/CVE-2026-75828)
- [VulnCheck Advisory: Grav before 2.0.15 Stored XSS via detectXss() Quote Bypass](https://www.vulncheck.com/advisories/grav-before-stored-xss-via-detectxss-quote-bypass)

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Source page: https://erroneo.us/security/cve/CVE-2026-75828/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt