⚠ Reference material — not professional advice. Test in staging, back up first, verify against your specific version. Use your own judgment for your environment.
● Medium · CVSS 4.7

How to Fix CVE-2026-2813: Open Redirect in ArcGIS Server

Other vulnerabilities in the same area that are worth patching alongside this one:

*By Sai Kiran Pandrala*

⚡ At a glance
SeverityCVSS 4.7 - Medium
Actively exploited?Not currently listed in CISA KEV
Affected11.5
Fixed inSee vendor advisory
Type (CWE)Not verified

What is CVE-2026-2813?

CVE-2026-2813 is an open-redirect flaw in ArcGIS Server. The product forwards users to a URL taken from a parameter without validating the destination, which phishing campaigns use to abuse the product's trusted domain. Vendor description: ArcGIS Server contains an input validation weakness in the login redirection workflow. An Authenticated attacker could exploit this issue by sending a specially crafted request, Successful exploitation may result in the application redirecting the browser to an unintended, untrusted site, resulting in a limited confidentiality impact under specific user interaction conditions.

Why this CVE matters

Open redirects on a trusted domain are routinely used by phishing kits to land victims on credential-harvesting pages while bouncing through a domain the victim trusts.

For deployments of ArcGIS Server that have been exposed to the public internet during the disclosure window, the operating assumption should be that scanning has already happened. Even where exploitation has not been publicly observed, scanning for the vulnerable fingerprint is cheap and routine. Patching closes the door; log review and credential rotation close out the rest of the response.

Am I affected?

You are affected if your installation matches any of these version ranges:

Check your installed version against the list above. If you cannot determine the version, treat the system as affected and follow the upgrade path below.

Open ArcGIS Server's About dialog or run the vendor-documented version-check command. Compare the result against the affected ranges in the advisory.

How to fix CVE-2026-2813

  1. Read the vendor advisory in full: https://www.esri.com/arcgis-blog/products/trust-arcgis/administration/april2026_security_bulletin
  2. Upgrade ArcGIS Server to the patched build listed in the vendor advisory.
  3. Back up the configuration (and database, where applicable) before upgrading.
  4. Apply the patch in a maintenance window. For HA pairs, upgrade the standby node first, fail over, then upgrade the former primary.
  5. Restart the affected service so the patched binary loads, then verify the new version (see verification section).

The commands below are runnable starting points. Adapt the package name, target version, and host paths to your environment using the vendor advisory linked under References.

Ubuntu / Debian


sudo apt-get update
sudo apt-get install --only-upgrade arcgisserver
dpkg -s arcgisserver | grep -i version

RHEL / CentOS / Rocky / AlmaLinux


sudo dnf upgrade --refresh arcgisserver -y
rpm -q arcgisserver

Container image


# Vendor advisory: https://www.esri.com/arcgis-blog/products/trust-arcgis/administration/april2026_security_bulletin
docker pull <your-registry>/arcgisserver:<patched-tag>
docker build -t <your-app>:patched .
docker stop <your-app> && docker rm <your-app>
docker run -d --name <your-app> <your-app>:patched

PowerShell detect/upgrade/verify/log (Windows)


# CVE-2026-2813 remediation runner. Adapt version checks to your environment.
$log = "C:\Logs\CVE-2026-2813-fix.log"
New-Item -ItemType Directory -Force -Path (Split-Path $log) | Out-Null
function Write-Log($msg) { "$(Get-Date -Format s) $msg" | Out-File $log -Append }

try {
    Write-Log "Detect: checking installed product"
    $installed = Get-CimInstance Win32_Product -ErrorAction SilentlyContinue |
        Where-Object { $_.Name -match 'ArcGIS Server' }
    if (-not $installed) { Write-Log "Product not installed; nothing to do"; return }
    Write-Log "Found version $($installed.Version)"

    Write-Log "Backup: copying program files and registry hive"
    $stamp = Get-Date -Format yyyyMMdd-HHmm
    $backup = "C:\Backup\CVE-2026-2813-$stamp"
    New-Item -ItemType Directory -Force -Path $backup | Out-Null
    Copy-Item $installed.InstallLocation $backup -Recurse -ErrorAction SilentlyContinue
    reg export HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall "$backup\uninstall.reg" /y | Out-Null

    Write-Log "Upgrade: install patched build via vendor MSI / Windows Update"
    Install-WindowsUpdate -AcceptAll -AutoReboot -ErrorAction SilentlyContinue

    Write-Log "Verify: re-reading product version"
    $after = Get-CimInstance Win32_Product | Where-Object { $_.Name -match 'ArcGIS Server' }
    Write-Log "Post-patch version: $($after.Version)"
    if ($after.Version -ne $installed.Version) { Write-Log "SUCCESS: version changed" } else { Write-Log "WARN: version unchanged; check vendor advisory" }
} catch {
    Write-Log "ERROR: $_"
    throw
}

Bash detect/upgrade/verify/log (Linux)


#!/usr/bin/env bash
# CVE-2026-2813 remediation runner. Re-runnable, exits non-zero on failure.
set -euo pipefail
log() { printf '%s %s\n' "$(date -Is)" "$*" | tee -a /var/log/cve-2026-2813-fix.log; }

log "Detect: current arcgisserver version"
if command -v dpkg >/dev/null 2>&1; then
    current=$(dpkg-query -W -f='${Version}' arcgisserver 2>/dev/null || echo "not-installed")
elif command -v rpm >/dev/null 2>&1; then
    current=$(rpm -q --qf '%{VERSION}-%{RELEASE}' arcgisserver 2>/dev/null || echo "not-installed")
else
    current="unknown"
fi
log "Current: $current"

log "Backup: snapshotting config"
backup="/var/backups/cve-2026-2813-$(date +%Y%m%d-%H%M)"
mkdir -p "$backup"
[ -d /etc/arcgisserver ] && cp -a /etc/arcgisserver "$backup/" || true

log "Upgrade: applying vendor patch"
if command -v apt-get >/dev/null 2>&1; then
    sudo apt-get update -qq
    sudo apt-get install -y --only-upgrade arcgisserver
elif command -v dnf >/dev/null 2>&1; then
    sudo dnf upgrade -y arcgisserver
elif command -v yum >/dev/null 2>&1; then
    sudo yum update -y arcgisserver
fi

log "Verify: re-reading arcgisserver version"
if command -v dpkg >/dev/null 2>&1; then
    after=$(dpkg-query -W -f='${Version}' arcgisserver)
else
    after=$(rpm -q --qf '%{VERSION}-%{RELEASE}' arcgisserver)
fi
log "After: $after"

if [ "$after" != "$current" ]; then
    log "SUCCESS: arcgisserver upgraded"
else
    log "WARN: version unchanged. Confirm the patched build is in your repository."
    exit 1
fi

If you cannot patch immediately

Block the redirect parameter at a reverse proxy, or strip it from inbound requests. Patch as the durable fix.

How to verify the fix worked

If your installation was internet-reachable during the disclosure window, treat log review as part of the remediation rather than an optional follow-up. Look for log entries that do not match your normal request patterns, especially repeated requests to the same uncommon endpoint, and any administrative changes you cannot tie back to a known operator.

Frequently asked questions

Is CVE-2026-2813 being exploited in the wild?

Public exploitation has not been confirmed by CISA at the time of writing. Treat the patch as time-sensitive anyway; reports often lag actual abuse.

Will a WAF or IDS rule fully mitigate CVE-2026-2813?

No. Network-layer filters can reduce noise and slow opportunistic scanners, but they will not stop a determined attacker. The vendor patch is the only durable fix.

How long should I plan for the upgrade?

Typical vendor-documented upgrade windows for ArcGIS Server run from a few minutes to under an hour depending on cluster size. Test in a staging environment first and follow the vendor's documented HA upgrade order.

References

*This guide was assembled from the official vendor advisory, the NVD record, and the CISA KEV catalog entry on 2026-05-25. Always confirm against the vendor advisory before applying changes in production.*