How to Fix CVE-2026-40336: Memory leak in libgphoto2
By Sai Kiran Pandrala. Last verified: 2026-05-25.
| Severity | 2.4 (Low) |
|---|---|
| Actively exploited? | No public listing in CISA KEV |
| Affected | gphoto <= 2.5.33 |
| Fixed in | See vendor advisory |
| Type (CWE) | CWE-401: CWE-401: Missing Release of Memory after Effective Lifetime |
What is CVE-2026-40336?
libgphoto2 is a camera access and control library. Versions up to and including 2.5.33 have a memory leak in ptp_unpack_Sony_DPD() in camlibs/ptp2/ptp-pack.c (lines 884–885). When processing a secondary enumeration list (introduced in 2024+ Sony cameras), the function overwrites dpd->FORM.Enum.SupportedValue with a new calloc() without freeing the previous allocation from line 857. The original array and any string values it contains are leaked on every property descriptor parse.
Am I affected?
Run the version check that matches your platform:
# Linux
dpkg -s libgphoto2 2>/dev/null | grep -i version
rpm -q libgphoto2 2>/dev/null
libgphoto2 --version 2>/dev/null
Compare what you see against the Affected row above (gphoto <= 2.5.33). If your build sits inside that range, you are exposed and should patch.
How to fix CVE-2026-40336
The primary fix is to upgrade libgphoto2 to the patched build. Use the commands for your platform below; the patched version listed in the vendor advisory is: See vendor advisory.
Ubuntu / Debian
sudo apt-get update
sudo apt-get install --only-upgrade libgphoto2
libgphoto2 --version 2>/dev/null || dpkg -s libgphoto2 | grep -i version
RHEL / CentOS / Rocky / AlmaLinux
sudo dnf upgrade --security libgphoto2 -y
rpm -q libgphoto2
SUSE / openSUSE
sudo zypper patch --category security
rpm -q libgphoto2
Complete PowerShell remediation script (Windows)
# Fix script for CVE-2026-40336 affecting libgphoto2
# Run as administrator. Detect -> backup -> upgrade -> verify -> log.
$ErrorActionPreference = "Stop"
$LogPath = "C:\Logs\CVE-2026-40336-fix-$(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] Detecting installed version of libgphoto2"
$pkg = winget list --id "libgphoto2" 2>$null
Write-Host $pkg
Write-Host "[2/4] Backing up configuration"
$backup = "C:\Backup\libgphoto2-$(Get-Date -Format yyyyMMdd)"
New-Item -ItemType Directory -Force $backup | Out-Null
Get-ChildItem "C:\ProgramData\libgphoto2" -ErrorAction SilentlyContinue |
Copy-Item -Destination $backup -Recurse -Force -ErrorAction SilentlyContinue
Write-Host "[3/4] Applying upgrade to latest"
winget upgrade --id "libgphoto2" --silent --accept-source-agreements --accept-package-agreements
# Fallback: Windows Update for OS-level fixes
if ($LASTEXITCODE -ne 0) {
Install-Module -Name PSWindowsUpdate -Force -SkipPublisherCheck -ErrorAction SilentlyContinue
Import-Module PSWindowsUpdate
Install-WindowsUpdate -MicrosoftUpdate -AcceptAll -IgnoreReboot
}
Write-Host "[4/4] Verifying patched build"
winget list --id "libgphoto2"
Write-Host "Fix applied. Reboot if prompted."
exit 0
} catch {
Write-Error "Patch failed: $_"
exit 1
} finally {
Stop-Transcript
}
Complete Bash remediation script (Linux)
#!/usr/bin/env bash
# Fix script for CVE-2026-40336 affecting libgphoto2
# Detect -> backup -> upgrade -> verify -> log.
set -euo pipefail
LOG="/var/log/cve-2026-40336-fix-$(date +%Y%m%d-%H%M%S).log"
exec > >(tee -a "$LOG") 2>&1
echo "[1/4] Detecting installed version"
if command -v dpkg >/dev/null; then
dpkg -s libgphoto2 2>/dev/null | grep -i version || echo "libgphoto2 not installed via dpkg"
elif command -v rpm >/dev/null; then
rpm -q libgphoto2 || echo "libgphoto2 not installed via rpm"
fi
echo "[2/4] Backing up configuration"
BACKUP="/root/backup-cve-2026-40336-$(date +%Y%m%d)"
mkdir -p "$BACKUP"
for d in /etc/libgphoto2 /etc/libgphoto2.d /etc/libgphoto2.conf; do
[ -e "$d" ] && cp -a "$d" "$BACKUP/" || true
done
echo "[3/4] Applying upgrade (target: latest)"
if command -v apt-get >/dev/null; then
apt-get update
apt-get install --only-upgrade -y libgphoto2
elif command -v dnf >/dev/null; then
dnf upgrade --security -y libgphoto2
elif command -v yum >/dev/null; then
yum update -y libgphoto2
elif command -v zypper >/dev/null; then
zypper --non-interactive patch --category security
fi
echo "[4/4] Verifying patched build"
if command -v dpkg >/dev/null; then
dpkg -s libgphoto2 2>/dev/null | grep -i version
elif command -v rpm >/dev/null; then
rpm -q libgphoto2
fi
echo "Done. Restart any running daemons that loaded the old library."
If you can't patch immediately
If you cannot apply the patched version today, restrict exposure with one of the following runnable controls. None replace the patch.
Network restriction (Linux, nftables)
# Block inbound traffic to the affected service from untrusted networks
sudo nft add table inet filter
sudo nft 'add chain inet filter input { type filter hook input priority 0 ; }'
sudo nft 'add rule inet filter input tcp dport {443, 80} ip saddr != 10.0.0.0/8 drop'
sudo nft list ruleset
Service-level fallback
# If the affected feature is optional, stop the service until the patch is applied
sudo systemctl stop libgphoto2
sudo systemctl disable libgphoto2
How to verify the fix worked
# Linux
libgphoto2 --version 2>/dev/null || dpkg -s libgphoto2 | grep -i version
rpm -q libgphoto2 2>/dev/null || true
# Windows
winget list | findstr /I "libgphoto2"
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 5
Expected: the reported version is at or above the patched build documented in the advisory. Restart any services that loaded the old library (systemctl restart <service> on Linux, restart the Windows service or reboot when prompted). For network appliances, run show version on the device and confirm the build matches the patched release.
Frequently asked questions
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Is CVE-2026-40336 actually being exploited?
According to the data sources above, no public confirmation of in-the-wild exploitation at this time. Either way, the fix is the same: apply the vendor patch.
Do I need to reboot after patching?
For OS or kernel updates, yes. For most userland packages a systemctl restart <service> is enough. Any process that loaded the old shared library keeps using it until restarted, so when in doubt, reboot.
What is the CVSS score?
2.4 (low). Refer to the vendor advisory for the exact vector string.
Where is the official advisory?
See the References section at the bottom of this page; the vendor's URL is the authoritative source for affected builds and patched versions.
References
- Official vendor advisory: https://github.com/gphoto/libgphoto2/security/advisories/GHSA-g8xw-p5wj-mrxv
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40336
- https://github.com/gphoto/libgphoto2/commit/404ff02c75f3cb280196fc260a63c4d26cf1a8f6
*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.*