How to Fix CVE-2026-28789: Concurrent execution using shared resource with improper synchronization ('race condition') in OliveTin
By Sai Kiran Pandrala. Last verified: 2026-05-25.
CVE-2026-28789 is a concurrent execution using shared resource with improper synchronization ('race condition') in OliveTin OliveTin. The fix is to apply the vendor patch noted below.
| Severity | 7.5 (High) |
|---|---|
| Actively exploited? | No public listing in CISA KEV |
| Affected | OliveTin < 3000.10.3 |
| Fixed in | See vendor advisory |
| Type (CWE) | CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') |
What is CVE-2026-28789?
OliveTin gives access to predefined shell commands from a web interface. Prior to version 3000.10.3, an unauthenticated denial-of-service vulnerability exists in OliveTin’s OAuth2 login flow. Concurrent requests to /oauth/login can trigger unsynchronized access to a shared registeredStates map, causing a Go runtime panic (fatal error: concurrent map writes) and process termination. This allows remote attackers to crash the service when OAuth2 is enabled. This issue has been patched in version 3000.10.3. The CVSS base score is 7.5 (High), which puts this in the upper risk band and warrants a fast patch cycle. The official advisory is at https://github.com/OliveTin/OliveTin/security/advisories/GHSA-45m3-398w-m2m9.
Am I affected?
Check the version of OliveTin you are running and compare it against the Affected row above (OliveTin < 3000.10.3). If your build sits inside the affected range, you must patch.
Run the version check that fits your platform:
# Linux package check
dpkg -s olivetin 2>/dev/null | grep -i ^Version
rpm -q olivetin 2>/dev/null
command -v olivetin >/dev/null && olivetin --version 2>/dev/null
# Windows (PowerShell)
Get-Package -Name "*OliveTin*" -ErrorAction SilentlyContinue | Select-Object Name, Version
winget list --name "OliveTin" 2>$null
How to fix CVE-2026-28789
Upgrade OliveTin to a patched build: See vendor advisory. The vendor advisory is the source of truth for the exact fixed version.
Ubuntu / Debian
sudo apt-get update
sudo apt-get install --only-upgrade olivetin
dpkg -s olivetin | grep -i ^Version
RHEL / CentOS / Rocky / AlmaLinux
sudo dnf upgrade --refresh olivetin -y
# or for older releases:
sudo yum update olivetin -y
rpm -q olivetin
SUSE / openSUSE
sudo zypper refresh
sudo zypper update olivetin
rpm -q olivetin
Node.js / npm
# Update the affected package in your project
npm install OliveTin@latest
npm ls OliveTin
npm audit fix
Complete PowerShell remediation script (Windows)
# Fix script for CVE-2026-28789 affecting OliveTin
# Run as administrator. Detect -> backup -> upgrade -> verify -> log.
$ErrorActionPreference = "Stop"
$LogPath = "C:\Logs\CVE-2026-28789-fix-$(Get-Date -Format yyyyMMdd-HHmmss).log"
New-Item -ItemType Directory -Force (Split-Path $LogPath) | Out-Null
Start-Transcript -Path $LogPath -Append
try {
Write-Host "[1/4] Detect installed version"
$pkg = Get-Package -Name "*OliveTin*" -ErrorAction SilentlyContinue
if ($pkg) { $pkg | Format-Table Name, Version }
else { Write-Host "Not detected via Get-Package; try winget list" }
Write-Host "[2/4] Backup configuration"
$backup = "C:\Backup\olivetin-$(Get-Date -Format yyyyMMdd)"
New-Item -ItemType Directory -Force $backup | Out-Null
Get-ChildItem "C:\ProgramData\OliveTin" -ErrorAction SilentlyContinue |
Copy-Item -Destination $backup -Recurse -Force -ErrorAction SilentlyContinue
Write-Host "[3/4] Apply the upgrade to See vendor advisory"
winget upgrade --name "OliveTin" --silent --accept-source-agreements --accept-package-agreements
if ($LASTEXITCODE -ne 0) {
# Fallback: pull latest via OS update channel
Install-Module -Name PSWindowsUpdate -Force -SkipPublisherCheck -ErrorAction SilentlyContinue
Import-Module PSWindowsUpdate
Install-WindowsUpdate -MicrosoftUpdate -AcceptAll -IgnoreReboot
}
Write-Host "[4/4] Verify the patched build"
winget list --name "OliveTin"
Write-Host "Patch applied. Reboot if prompted."
exit 0
} catch {
Write-Error "Patch failed: $_"
exit 1
} finally {
Stop-Transcript
}
Complete Bash remediation script (Linux)
#!/usr/bin/env bash
# Fix script for CVE-2026-28789 affecting OliveTin
# Detect -> backup -> upgrade -> verify -> log.
set -euo pipefail
LOG="/var/log/cve-2026-28789-fix-$(date +%Y%m%d-%H%M%S).log"
exec > >(tee -a "$LOG") 2>&1
echo "[1/4] Detect installed version"
if command -v dpkg >/dev/null; then
dpkg -s olivetin 2>/dev/null | grep -i ^Version || echo "olivetin not installed via dpkg"
elif command -v rpm >/dev/null; then
rpm -q olivetin || echo "olivetin not installed via rpm"
fi
echo "[2/4] Backup configuration"
BACKUP="/root/backup-cve-2026-28789-$(date +%Y%m%d)"
mkdir -p "$BACKUP"
for d in /etc/olivetin /etc/olivetin.d /etc/olivetin.conf; do
[ -e "$d" ] && cp -a "$d" "$BACKUP/" || true
done
echo "[3/4] Apply the upgrade (target: See vendor advisory)"
if command -v apt-get >/dev/null; then
apt-get update
apt-get install --only-upgrade -y olivetin
elif command -v dnf >/dev/null; then
dnf upgrade --refresh -y olivetin
elif command -v yum >/dev/null; then
yum update -y olivetin
elif command -v zypper >/dev/null; then
zypper --non-interactive update olivetin
fi
echo "[4/4] Verify the patched build"
if command -v dpkg >/dev/null; then
dpkg -s olivetin 2>/dev/null | grep -i ^Version
elif command -v rpm >/dev/null; then
rpm -q olivetin
fi
echo "Done. Restart any service that loaded the old library."
If you can't patch immediately
Apply at least one of the following inline controls until you can deploy the patched build. None replace the upgrade.
Restrict exposure with nftables (Linux)
# Allow only trusted CIDR to reach the affected service ports
sudo nft add table inet filter 2>/dev/null || true
sudo nft 'add chain inet filter input { type filter hook input priority 0 ; }' 2>/dev/null || true
sudo nft 'add rule inet filter input tcp dport {80, 443} ip saddr != 10.0.0.0/8 drop'
sudo nft list ruleset
Block at the host firewall (Windows)
New-NetFirewallRule -DisplayName "Block-CVE-2026-28789" -Direction Inbound -Action Block -Protocol TCP -LocalPort 80,443 -RemoteAddress Any -Enabled True
Get-NetFirewallRule -DisplayName "Block-CVE-2026-28789"
Disable the affected service (Linux)
sudo systemctl stop olivetin 2>/dev/null || true
sudo systemctl disable olivetin 2>/dev/null || true
If the vendor advisory lists an official workaround, prefer that wording verbatim. If no workaround is published, the only safe remediation is the patch.
How to verify the fix worked
After upgrading, confirm the installed version matches the patched build and that no old library is still loaded by a long-running process.
# Linux
dpkg -s olivetin 2>/dev/null | grep -i ^Version
rpm -q olivetin 2>/dev/null || true
# Pid map check for old library handles
sudo lsof +c0 2>/dev/null | grep -i "DEL.*lib" || true
# Windows
Get-Package -Name "*OliveTin*" | Select-Object Name, Version
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 5
Expected: the reported version is at or above See vendor advisory. Restart the affected service (systemctl restart <service> on Linux, or restart the Windows service) so it loads the patched binary.
Frequently asked questions
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Is CVE-2026-28789 actively exploited?
There is no public confirmation of exploitation in the wild listed in CISA KEV at the time of this writing. Patch anyway. Public exploits commonly follow disclosure within weeks.
Do I need to reboot after patching CVE-2026-28789?
For kernel and OS-level updates, yes. For most userland packages a systemctl restart <service> is enough on Linux, and restarting the Windows service or app on Windows. Any process that loaded the old library keeps using it until restarted.
What is the CVSS score for CVE-2026-28789?
7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Where is the official advisory for CVE-2026-28789?
The vendor advisory is at https://github.com/OliveTin/OliveTin/security/advisories/GHSA-45m3-398w-m2m9. The NVD record is at https://nvd.nist.gov/vuln/detail/CVE-2026-28789.
References
- Official vendor advisory: https://github.com/OliveTin/OliveTin/security/advisories/GHSA-45m3-398w-m2m9
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-28789
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Additional reference: https://github.com/OliveTin/OliveTin/commit/f044d90d5525c4c8e3f421b32ed7eff771c22d36
*Written by Sai Kiran Pandrala. Assembled from the official vendor advisory, NVD record, and CISA KEV listing on 2026-05-25. Always confirm against the vendor's advisory before applying changes in production.*