apko /etc/passwd and /etc/group UID/GID truncation writes package-supplied entries as root
apko allows users to build and publish OCI container images built from apk packages. From version 0.2.0 to before version 1.4.5, UserEntry.Parse and GroupEntry.Parse in pkg/passwd read the UID and GID fields of /etc/passwd and /etc/group entries with strconv.Atoi and convert them to uint32 without a range check. On 64-bit platforms an out-of-range value such as 4294967296 (2^32) is truncated to 0, and negative values wrap. Because apko parses the passwd and group entries supplied by the packages it installs and writes them back into the image, an attacker who controls a package installed into the image can ship an entry that appears to declare an unprivileged UID or GID but is written into the built image as UID 0 or GID 0 (root). The truncated UID is also used when resolving the image's run-as user. This issue has been fixed in version 1.4.5.
CVE-2026-105768
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-105768
apko
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://github.com/chainguard-dev/apko",
"vendor": "chainguard-dev",
"modules": [
"pkg/passwd"
],
"product": "apko",
"versions": [
{
"status": "affected",
"version": "0.2.0",
"lessThan": "1.4.5",
"versionType": "semver"
}
],
"packageName": "chainguard.dev/apko",
"programFiles": [
"pkg/passwd/passwd.go",
"pkg/passwd/group.go"
],
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "passwd.UserEntry.Parse"
},
{
"name": "passwd.GroupEntry.Parse"
}
]
}
]- Related CVEs
- CVE-2026-105768
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #9299 · Revision 1
- Added to Heist Feed
- Publisher date