CVE-2026-104252
Vitess is a database clustering system for horizontal scaling of MySQL.
Published Oct 13, 2026 · corrected/updated Oct 15, 2026 · evidence confidence high
From: xylove21 To: security@vitess.io Subject: [Security Report] Vitess vttablet /twopcz reflected XSS Date: Tue, 24 Jun 2026 14:30:00 +0800 ## Summary The in (line 185) reflects the and form values directly into the HTML response body via — **without HTML escaping**. The response is served as , and Vitess's default policy is **allow-all**, so the endpoint is reachable by anyone who can hit the vttablet's HTTP port (default , multiplexed with gRPC and MySQL wire-protocol ports). A crafted or value yields a **reflected XSS** that executes in the operator's browser with same-origin access to the vttablet's debug endpoints. This includes (live query plans), (recent queries with bound values), (transactions), (environment variables — may include MySQL/topology credentials), (expvar stats), and if enabled. The bug was introduced before v20.0.0 (long-standing) and was silently fixed in commit (merged 2026-06-09, PR #20255, "tabletserver: escape reflected form values in twopcz handler"). The fix replaces with . **No released version of Vitess contains the fix** — the fix lives only on (current tip , 2026-06-23). There is **no CVE, GHSA, or OSV entry** for this specific bug (verified 2026-06-24 against GitHub Advisory Database, OSV.dev, and NVD). ## Impact | Field | Value | |-------|-------| | **Type** | Reflected Cross-Site Scripting (XSS) | | **CVSS 3.1** | = **7.7 HIGH** | | **Attack Vector** | Network (vttablet HTTP port 15999, multiplexed with gRPC/MySQL) | | **Attack Complexity** | Low (craft URL, send to operator) | | **Privileges Required** | None (default policy is allow-all) | | **User Interaction** | Required (operator must visit crafted URL) | | **Scope** | Changed (XSS chain reaction to other vttablet debug endpoints) | | **Confidentiality** | High (query text, env vars, expvar stats) | | **Integrity** | None (XSS itself doesn't change state) | | **Availability** | None (XSS itself doesn't disrupt service) | ### Affected versions (verified) All released version
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-104252 is a critical public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: vitess.io/vitess (< 0.23.5); vitess.io/vitess (>= 0.24.0, < 0.24.2); vitess.io. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 9.8, EPSS 0.9%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-116, CWE-79, CWE-80. Sources contributing to this record: cve_org, epss, github, gitlab. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in the CISA KEV catalog.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Oct 13, 2026 · NIST NVD
Detected
Vitess is a database clustering system for horizontal scaling of MySQL. Prior to 23.0.5 and 24.0.2, twopczHandler in go/vt/vttablet/tabletserver/twopcz.go writes the Action and dtid form values from the vttablet and vtcombo /twopcz HTTP debug endpoint into a text/html response without HTML escaping. Under the default allow-all ACL policy, a remote unauthenticated attacker can send an operator a cr
Oct 15, 2026 · NIST NVD
Updated
Vitess is a database clustering system for horizontal scaling of MySQL. Prior to 23.0.5 and 24.0.2, twopczHandler in go/vt/vttablet/tabletserver/twopcz.go writes the Action and dtid form values from the vttablet and vtcombo /twopcz HTTP debug endpoint into a text/html response without HTML escaping. Under the default allow-all ACL policy, a remote unauthenticated attacker can send an operator a cr
Oct 15, 2026 · GitHub Advisory Database
Updated
From: xylove21 To: security@vitess.io Subject: [Security Report] Vitess vttablet /twopcz reflected XSS Date: Tue, 24 Jun 2026 14:30:00 +0800 ## Summary The in (line 185) reflects the and form values directly into the HTML response body via — **without HTML escaping**. The response is served as , and Vitess's default policy is **allow-all**, so the endpoint is reachable by anyone who can hit the vt
Affected
- go vitess.io/vitess< 0.23.5
- go vitess.io/vitess>= 0.24.0, < 0.24.2
- golang vitess.ioversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-104252
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-104252
30-day exploitation probability 0.9%
first.org - GitHub Advisory DatabasePackage advisoryGHSA-v75v-6fpf-gvw8
Vitess vttablet /twopcz reflected XSS
github.com - GitLab Advisory DatabasePackage advisoryCVE-2026-104252
The twopczHandler in go/vt/vttablet/tabletserver/twopcz.go (line 185) reflects the Action and dtid form values directly into the HTML response body via fmt.Fprintln(w, msg) — without HTML escaping. The response is served as text/html; charset=utf-8, and Vitess's default acl policy is allow-all, so the endpoint is reachable by anyone who can hit the vttablet's HTTP port (default 15999, multiplexed
advisories.gitlab.com - NIST NVDVulnerability recordCVE-2026-104252
Vitess is a database clustering system for horizontal scaling of MySQL. Prior to 23.0.5 and 24.0.2, twopczHandler in go/vt/vttablet/tabletserver/twopcz.go writes the Action and dtid form values from the vttablet and vtcombo /twopcz HTTP debug endpoint into a text/html response wi
nvd.nist.gov