CVE-2026-105768: medium-severity vulnerability in chainguard-dev apko
apko /etc/passwd and /etc/group UID/GID truncation writes package-supplied entries as root
Published · Updated
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.3epss 0.3%
exploitation probability
0.3%top 79% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
Affected products
chainguard-dev · apkoRelated CVEs — chainguard-dev apko
In the same product, most dangerous first.
CVE-2026-42574HIGHapko dirFS has a symlink-following path traversal that allows multiple entry points to escape the build rootEPSS 0.5%CVE-2026-42576MEDIUMapko `DiscoverKeys` has a panic on non-rsa jwks key that causes crash during key discoveryEPSS 0.5%CVE-2024-36127HIGHapko Exposure of HTTP basic auth credentials in log outputEPSS 0.4%CVE-2026-25121HIGHapko is vulnerable to path traversal in apko dirFS which allows filesystem writes outside baseEPSS 0.4%CVE-2026-25140HIGHapko affected by potential unbounded resource consumption in expandapk.ExpandApk on attacker-controlled .apk streamsEPSS 0.4%CVE-2026-42575HIGHapko doesn't verify downloaded apk packages against APKINDEX checksum (package substitution possible)EPSS 0.2%