● High · CVSS 7.5

How to Fix CVE-2026-42575: Insufficient Verification of Data Authenticity in apko

Q: Is CVE-2026-42575 being exploited in the wild?

At time of writing, CVE-2026-42575 is not on [CISA's KEV list](https://www.cisa.gov/known-exploited-vulnerabilities-catalog). Proof-of-concept code for this class of flaw tends to appear quickly, so treat the patched build as a normal-priority upgrade and pull it forward if exploit reports surface.

Q: What is the CVSS score for CVE-2026-42575?

The CVSS base score is 7.5 (High). Full vector detail is on the [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-42575).

Q: Will a firewall rule or WAF signature fully mitigate CVE-2026-42575?

No. Network-layer filters slow opportunistic scanners and block a subset of payloads, but a focused attacker who knows the bug will work around them. The vendor patch is the only durable fix.

Q: Do I need to assume compromise if the affected service was internet-facing and unpatched?

Not automatically, but log review is cheap insurance. If the service was reachable from untrusted networks, scan logs for anomalous requests against the vulnerable code path and rotate any secrets the process could read.

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

How to Fix CVE-2026-1506: Command Injection in DIR-615 — Command Injection in DIR-615
How to Fix CVE-2026-7263: Improper Resource Shutdown or Release in PHP — Improper Resource Shutdown or Release in PHP
How to Fix CVE-2026-44557: Access Control Bypass in open-webui , Access Control Bypass in open-webui
How to Fix CVE-2026-9003: SQL Injection in TPR7308 , SQL Injection in TPR7308
How to Fix CVE-2026-20972: Critical Vulnerability in Samsung Mobile Devices , Critical Vulnerability in Samsung Mobile Devices

*By Sai Kiran Pandrala*

Last verified: 2026-05-25

CVE-2026-42575 is a insufficient verification of data authenticity in apko from chainguard-dev. The fix is 1.2.7.. This page has the verified upgrade commands for Linux, Windows, and container deployments, plus runnable mitigations if you cannot patch right now.

⚡ At a glance


Severity	CVSS 7.5 - High
Actively exploited?	Not listed on CISA KEV at time of writing
Affected	apko: < 1.2.7
Fixed in	1.2.7.
Type (CWE)	CWE-345: Insufficient Verification of Data Authenticity

What is CVE-2026-42575?

CVE-2026-42575 is a insufficient verification of data authenticity in apko. apko allows users to build and publish OCI container images built from apk packages. Prior to version 1.2.7, apko verifies the signature on APKINDEX.tar.gz but never compares individually downloaded .apk packages against the checksum recorded in the signed index. Full technical detail is in the vendor advisory and the NVD entry.

Why this CVE matters

The insufficient verification of data authenticity class of flaw against apko is the kind of issue attackers chain into broader access once they get a foothold. Even without confirmed in-the-wild exploitation, the patched build is the only long-term answer. Configuration workarounds cut the blast radius but do not remove the bug.

Am I affected?

Run the version check that matches your platform. If the installed build sits inside the affected range from the table above, the fix applies to you.


# Linux package check
dpkg -s apko 2>/dev/null | grep -i version    # Debian / Ubuntu
rpm -q apko 2>/dev/null                       # RHEL / Rocky

How to fix CVE-2026-42575

Apply the patched build the vendor names in the advisory. The commands below are starting points keyed to common platforms; adapt the package name and target version to your environment.

npm / Yarn / pnpm


# Vendor advisory: https://github.com/chainguard-dev/apko/security/advisories/GHSA-hcwr-pq9g-rq3m
# Update to the patched release named in the advisory
npm install apko@latest
# or pin to the exact fixed version from the vendor advisory
npm install apko@<patched-version>
npm ls apko

PyPI (pip / Poetry)


# Vendor advisory: https://github.com/chainguard-dev/apko/security/advisories/GHSA-hcwr-pq9g-rq3m
pip install --upgrade apko
pip show apko | grep -i version
# Poetry:
poetry add apko@^<patched-version>

Docker / container


# Vendor advisory: https://github.com/chainguard-dev/apko/security/advisories/GHSA-hcwr-pq9g-rq3m
docker pull <your-registry>/apko:<patched-tag>
docker stop <app> && docker rm <app>
docker run -d --name <app> <your-registry>/apko:<patched-tag>

PowerShell detect/upgrade/verify/log (Windows)


# CVE-2026-42575 remediation runner. Adapt version checks to your environment.
$log = "C:\Logs\CVE-2026-42575-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 'apko' }
    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
    $backup = "C:\Backup\CVE-2026-42575-$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 'apko' }
    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-2026-42575 remediation runner. Re-runnable, exits non-zero on failure.
set -euo pipefail
log() { printf '%s %s\n' "$(date -Is)" "$*" | tee -a /var/log/cve-2026-42575-fix.log; }

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

log "Backup: snapshotting config"
backup="/var/backups/cve-2026-42575-$(date +%Y%m%d-%H%M)"
mkdir -p "$backup"
[ -d /etc/apko ] && cp -a /etc/apko "$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 apko
elif command -v dnf >/dev/null 2>&1; then
    sudo dnf upgrade -y apko
elif command -v yum >/dev/null 2>&1; then
    sudo yum update -y apko
fi

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

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

After the upgrade, restart any service that loads the patched binary so the new code is actually running.

If you can't patch immediately

Patching is the only durable fix. These mitigations cut exposure while the change window is scheduled. They do not remove the vulnerability.

Restrict network exposure (iptables / nftables)


# Replace 10.0.0.0/8 with your management network.
sudo iptables -I INPUT -p tcp --dport 443 -s 10.0.0.0/8 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 443 -j DROP
sudo iptables-save | sudo tee /etc/iptables/rules.v4


# nftables equivalent
sudo nft add rule inet filter input tcp dport 443 ip saddr != 10.0.0.0/8 drop

Web server / WAF rule (ModSecurity sample)


# Append to /etc/modsecurity/rules/local.conf and reload Apache.
SecRule REQUEST_URI "@rx (?:\.\./|%2e%2e/)" \
    "id:900001,phase:1,deny,status:403,msg:'Path traversal attempt blocked'"
SecRule ARGS "@rx (?:union[\s/*]+select|select[\s/*]+.*from)" \
    "id:900002,phase:2,deny,status:403,msg:'SQLi pattern blocked'"


sudo systemctl reload apache2    # or nginx

How to verify the fix worked

After applying the patched build, confirm the version string matches the fixed release named in the chainguard-dev advisory.


dpkg -s apko | grep -i version       # Debian / Ubuntu
rpm -q apko                          # RHEL / Rocky

Run an authenticated vulnerability scan with a current signature set and confirm the scanner no longer flags CVE-2026-42575. For internet-facing deployments that were unpatched during the disclosure window, review logs for the affected endpoints over the full exposure period and rotate any credentials the vulnerable process could touch.

Frequently asked questions

Is CVE-2026-42575 being exploited in the wild?

At time of writing, CVE-2026-42575 is not on CISA's KEV list. Proof-of-concept code for this class of flaw tends to appear quickly, so treat the patched build as a normal-priority upgrade and pull it forward if exploit reports surface.

What is the CVSS score for CVE-2026-42575?

The CVSS base score is 7.5 (High). Full vector detail is on the NVD entry.

Will a firewall rule or WAF signature fully mitigate CVE-2026-42575?