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Atomicorp WAF Research Note: CVE-2026-48026

lakeFS vulnerable to stored XSS in rendered markdown previews via raw HTML

CVE Details

Already protected by existing Atomicorp WAF rules
Protection status: Understanding Atomicorp WAF Protection Status
CVE: CVE-2026-48026
Name: lakeFS vulnerable to stored XSS in rendered markdown previews via raw HTML
Severity: High
CVSS: 8.7 (v3.1) (High)
CVSS version: 3.1
CVSS source: GitHub_M CNA
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
- Attack vector: Network
- Attack complexity: Low
- Privileges required: Low
- User interaction: Required
- Scope: Changed
- Confidentiality impact: High
- Integrity impact: High
- Availability impact: None
CWE: CWE-79 — Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’)
Related CAPEC attack patterns (via MITRE CWE relationships): CAPEC-209 (opens in a new tab) , CAPEC-588 (opens in a new tab) , CAPEC-591 (opens in a new tab) , CAPEC-592 (opens in a new tab) , CAPEC-63 (opens in a new tab) , CAPEC-85 (opens in a new tab)
Vendor: treeverse
Vulnerable products: lakeFS , lakeFS-enterprise
CVE published: 2026-08-07
CVE last modified: 2026-09-09
EPSS: 0.0022; 12.3th percentile (FIRST (opens in a new tab) )
Latest Update: 2026-09-06
Selected Rule IDs observed: 333140 , 333141 , 340087 , 340095 , 340099 , 340147 , 340148 , 341099 , 341256 , 341266 , 342259 , 346755 , 350147 , 350148
Matching rules: 14; rules with blocking actions: 14
Would-block Rule IDs: 333140 , 333141 , 340087 , 340095 , 340099 , 340147 , 340148 , 341099 , 341256 , 341266 , 342259 , 346755 , 350147 , 350148
Request surfaces inspected: JSON request data, Request URI, Request argument names, Request arguments, Request cookies, Request filename, Request headers, SOAP request data, XML request data

Vulnerability Description

lakeFS is an open-source tool that transforms object storage into a Git-like repositories. Prior to version 1.81.1 of the open source edition and 1.84.0 of the enterprise edition, lakeFS Web UI renders markdown files from repository objects without sanitizing the resulting HTML. A user with write access to any repository branch can commit a .md object containing arbitrary HTML/JavaScript. Any other user who opens that object, or who navigates to a repository or directory containing a malicious README.md, executes the attacker-supplied script in their own authenticated session. lakeFS fixes the issue in v1.81.1 and lakeFS Enterprise fixes the issue in in v1.84.0. Enterprise customers using older versions can temporarily disable Markdown rendering by adding YAML to their config. No workaround exists for OSS release. Users are advised to upgrade to the latest version for both lakeFS and lakeFS-Enterprise.

Recommended Actions

Maintain the observed Atomicorp protections. Keep your Atomicorp commercial rules current and confirm that the selected observed rules (333140 , 333141 , 340087 , 340095 , 340099 , 340147 , 340148 , 341099 , 341256 , 341266 , 342259 , 346755 , 350147 , 350148 ) have not been locally disabled. Atomicorp commercial rules are enabled by default. If you use Atomic WAF, review the applicable policy and rule settings.
Apply the vendor’s remediation. WAF protection is defense in depth and does not replace upgrading or following the affected vendor’s guidance.
- Affected versions: treeverse lakeFS version < 1.81.1.
- Affected versions: treeverse lakeFS-enterprise version < 1.84.0.
- No specific CNA/vendor solution or workaround is included in the current CVE Record (opens in a new tab) . Review the vendor’s security advisories and supported-release guidance before making changes.
Validate after changes. Confirm rule updates are current, review WAF events for the affected application, and test application behavior after vendor upgrades, mitigations, or local policy changes.

Research Notes

Atomicorp WAF protections are designed around attack techniques and exploit behaviors, allowing existing protections to apply across multiple vulnerabilities without requiring a unique rule for every CVE.

Public Vulnerability References

Test or Research Source

Source: Atomicorp AI Research Framework
Tags: cve, derived, waf-probe, xss

Research Note Context

This research note documents exploit-technique analysis associated with this vulnerability and references Atomicorp WAF protections observed during engineering review, testing, or validation activities.

Atomicorp security controls are generally designed to identify and mitigate attack techniques and exploit behaviors rather than individual CVE identifiers. As a result, protections developed for one vulnerability may also apply to related attack variants and future vulnerabilities using similar techniques.

Learn More

Atomicorp develops commercially supported security technologies for web applications, servers, endpoints, workloads, and legacy enterprise platforms.

Organizations interested in protecting systems against exploit techniques associated with vulnerabilities such as this one can learn more about:

Atomic ModSecurity Rules: commercially maintained WAF rules for ModSecurity deployments, including protections for web attacks, bots, scanners, malware, exploitation attempts, and emerging vulnerability classes.
Atomic WAF: an enterprise web application firewall with Atomicorp rules, centralized management, reporting, authentication controls, and operational tooling.
Atomic ModSecurity Integrator: a special licensing option for MSPs, MSSPs, OEMs, VARs, reverse proxy providers, and other integrators who want to incorporate Atomicorp ModSecurity rule technology into their own products or services.
Atomic OSSEC: an enterprise OSSEC-based intrusion detection, compliance, and security monitoring platform.
Atomic Protector: workload protection for Linux, web, cloud, data center, and hybrid environments.

For additional information, product evaluations, or technical discussions, visit https://www.atomicorp.com/ or https://modsecurity.io/ (opens in a new tab) .