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Critical, CVSS 10.0

Server-Side Template Injection

CVE-2020-26282GHSA-wmfg-55f9-j8hq

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (com.browserup:browserup-proxy 2.1.2), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
10.0 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
EPSS
  • CVE-2020-26282: 4.83% estimated exploitation activity in the next 30 days; percentile 92.00 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Impact A Server-Side Template Injection was identified in BrowserUp Proxy enabling attackers to inject arbitrary Java EL expressions, leading to unauthenticated Remote Code Execution (RCE) vulnerability. This has been assigned CVE-2020-26282. Patches Effective Immediately, all users should upgrade to version 2.1.2 or higher. Workarounds None. References https://securitylab.github.com/research/bean-validation-RCE For more information If you have any questions or comments about this advisory: Open an issue in the BrowserUp Proxy repo Contact us via the BrowserUp website or email us at support@browserup.com

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-wmfg-55f9-j8hq

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2020-26282

Advisory: Server-Side Template Injection
IDs: CVE-2020-26282, GHSA-wmfg-55f9-j8hq
Record: https://patchnext.com/advisories/cve-2020-26282 (revision 1, source checked 26 Oct 2026, 16:06 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 10.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: com.browserup:browserup-proxy 2.1.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven com.browserup:browserup-proxy: affected < 2.1.2; fixed in 2.1.2

## Suggested inspection (read-only)
- Maven com.browserup:browserup-proxy: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on com.browserup:browserup-proxy.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-wmfg-55f9-j8hq (GitHub-reviewed advisory GHSA-wmfg-55f9-j8hq lists affected ranges: Maven com.browserup:browserup-proxy >=0 <2.1.2)

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