⚠ 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 6

How to Fix CVE-2026-22677: Path Traversal in hermes-webui

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

*By Sai Kiran Pandrala*

⚡ At a glance
SeverityCVSS 6 - Medium
Actively exploited?Not currently listed in CISA KEV
Affected0 < 0.51.44
Fixed inf00cb74f776f22f02f5eb6b39dfb389f87cc7fd3
Type (CWE)CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

What is CVE-2026-22677?

CVE-2026-22677 is a path traversal flaw in hermes-webui. The product fails to canonicalize or restrict file paths supplied by a remote caller, so .. sequences or absolute paths reach restricted parts of the filesystem. Vendor description: Hermes WebUI prior to 0.51.44 - Release T contains a path traversal vulnerability in the session import endpoint that allows authenticated attackers to read arbitrary files by importing a crafted session with an unrestricted workspace value. Attackers can supply a blocked filesystem root in the workspace field and subsequently use relative paths in the session file API to access any file readable by the WebUI process.

Why this CVE matters

Path traversal flaws look low-impact on paper but routinely chain into full compromise. An attacker who can read arbitrary files often pulls configuration secrets, session databases, or private keys, and many traversal bugs also allow writes that drop a webshell into the document root.

For deployments of hermes-webui 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 hermes-webui'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-2026-22677

  1. Read the vendor advisory in full: https://github.com/nesquena/hermes-webui/releases/tag/v0.51.44
  2. Upgrade hermes-webui to f00cb74f776f22f02f5eb6b39dfb389f87cc7fd3 or a later version 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).

Ubuntu / Debian

_Verify the exact patched build against the vendor advisory: https://github.com/nesquena/hermes-webui/commit/f00cb74f776f22f02f5eb6b39dfb389f87cc7fd3_


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

RHEL / Rocky / AlmaLinux / Fedora


sudo dnf upgrade --refresh hermes-webui -y
rpm -q hermes-webui

openSUSE


sudo zypper refresh
sudo zypper update hermes-webui
rpm -q hermes-webui

Bash detect / upgrade / verify runner (Linux)

_Verify the exact patched build against the vendor advisory: https://github.com/nesquena/hermes-webui/commit/f00cb74f776f22f02f5eb6b39dfb389f87cc7fd3_


#!/usr/bin/env bash
# CVE-2026-22677 remediation runner. Re-runnable; exits non-zero on failure.
set -euo pipefail
log() { printf '%s %s\n' "$(date -Is)" "$*" | tee -a /var/log/cve-2026-22677-fix.log; }

PKG="hermes-webui"
TARGET_VERSION="f00cb74f776f22f02f5eb6b39dfb389f87cc7fd3"

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/$PKG if present"
backup="/var/backups/cve-2026-22677-$(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: f00cb74f776f22f02f5eb6b39dfb389f87cc7fd3)
#    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-2026-22677.

# 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

Restrict access to the management interface to trusted internal IP addresses only. Block public access at the firewall and require VPN for any remote administration. Apply the patch as soon as a maintenance window allows.

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 unusually long URI paths containing traversal sequences, unexpectedly large responses from the affected endpoint, and outbound requests from the application to internal addresses or cloud-metadata endpoints. Treat any sensitive file the bug could disclose as exposed.

Frequently asked questions

Is CVE-2026-22677 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-2026-22677?

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 hermes-webui 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.*