● Medium · CVSS 5.4

How to Fix CVE-2026-22400: Critical Vulnerability in Holmes

Q: Is CVE-2026-22400 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.

Q: Will a WAF or IDS rule fully mitigate CVE-2026-22400?

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.

Q: How long should I plan for the upgrade?

Typical vendor-documented upgrade windows for Holmes 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.

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

How to Fix CVE-2026-40024: Sleuth Kit tsk_recover Path Traversal in sleuthkit — Sleuth Kit tsk_recover Path Traversal in sleuthkit
How to Fix CVE-2026-22414: Improper control of filename for include/require statement in php program ('php. — Improper control of filename for include/require statement in php program ('php.
How to Fix CVE-2026-3029: CVE-2026-3029 in PyMuPDF , CVE-2026-3029 in PyMuPDF
How to Fix CVE-2026-30914: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') , CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
How to Fix CVE-2026-35469: Allocation of resources without limits in spdystream , Allocation of resources without limits in spdystream

*By Sai Kiran Pandrala*

⚡ At a glance


Severity	CVSS 5.4 - Medium
Actively exploited?	Not currently listed in CISA KEV
Affected	0 <= 1.7
Fixed in	See vendor advisory
Type (CWE)	CWE-639: Authorization Bypass Through User-Controlled Key

What is CVE-2026-22400?

CVE-2026-22400 is a security flaw in Holmes. Authorization Bypass Through User-Controlled Key vulnerability in Mikado-Themes Holmes holmes allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Holmes: from n/a through <= 1.7.

Why this CVE matters

Unpatched network-facing software is the leading initial-access vector in public breach reporting. Treat any CVSS-9 class flaw on an internet-reachable system as urgent, regardless of whether public exploit code has been observed yet.

For deployments of Holmes 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:

Holmes: 0 <= 1.7

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 Holmes'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-2026-22400

Read the vendor advisory in full: https://patchstack.com/database/Wordpress/Theme/holmes/vulnerability/wordpress-holmes-theme-1-7-insecure-direct-object-references-idor-vulnerability?_s_id=cve
Upgrade Holmes to the patched build listed in the vendor advisory.
Back up the configuration (and database, where applicable) before upgrading.
Apply the patch in a maintenance window. For HA pairs, upgrade the standby node first, fail over, then upgrade the former primary.
Restart the affected service so the patched binary loads, then verify the new version (see verification section).

Ubuntu / Debian

_Verify the exact patched build against the vendor advisory: https://patchstack.com/database/Wordpress/Theme/holmes/vulnerability/wordpress-holmes-theme-1-7-insecure-direct-object-references-idor-vulnerability?_s_id=cve_


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

RHEL / Rocky / AlmaLinux / Fedora


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

openSUSE


sudo zypper refresh
sudo zypper update holmes
rpm -q holmes

Bash detect / upgrade / verify runner (Linux)


#!/usr/bin/env bash
# CVE-2026-22400 remediation runner. Re-runnable; exits non-zero on failure.
set -euo pipefail
log() { printf '%s %s\n' "$(date -Is)" "$*" | tee -a /var/log/cve-2026-22400-fix.log; }

PKG="holmes"
TARGET_VERSION="see vendor advisory"

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

log "Backup: snapshotting /etc/$PKG if present"
backup="/var/backups/cve-2026-22400-$(date +%Y%m%d-%H%M)"
mkdir -p "$backup"
[ -d "/etc/$PKG" ] && cp -a "/etc/$PKG" "$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 "$PKG"
elif command -v dnf >/dev/null 2>&1; then
    sudo dnf upgrade -y "$PKG"
elif command -v yum >/dev/null 2>&1; then
    sudo yum update -y "$PKG"
fi

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

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

Verify the fix landed


# 1. Confirm the running version matches the patched build
#    (target per advisory: see vendor advisory)
#    Use the platform-specific version probe shown above.

# 2. Re-scan the host with your vulnerability scanner (Nessus, Qualys, Tenable,
#    Rapid7, OpenVAS). The scanner should no longer flag CVE-2026-22400.

# 3. Inspect service and kernel logs for crash-loops or rollback events
journalctl --since "10 minutes ago" | grep -iE 'error|fail|panic'
dmesg --since "10 minutes ago" | tail -50

If you cannot patch immediately

No official workaround exists beyond restricting network exposure to the affected component. Apply the vendor patch as the primary remediation.

How to verify the fix worked

After applying the patch, verify the running version in the product's admin UI or via the vendor-documented CLI command.
Confirm the patched build matches the version listed in the vendor advisory.
Run an authenticated vulnerability scan with a current signature set and confirm the scanner no longer flags CVE-2026-22400.
Review logs for the entire pre-patch window for indicators of compromise listed in the vendor or CISA advisory.
Confirm any network-layer mitigations that were applied as a stopgap have been reverted (or left in place intentionally) once the patch is verified.

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-2026-22400 being exploited in the wild?