esm.sh writes arbitrary files via path traversal in `X-Zone-Id` header
48Vexday Risk Score
Patch soon. It has a working public exploit.
ssvc Attendcvss 5.5epss 2.8%
from disclosure to weapon1 days
Published on NVDSep 17
1st PoC+1d
exploitation probability
2.8%top 15% of all CVEs
observed exploitation
nono source reports it
2 public exploit(s)
esm.sh is a nobuild content delivery network(CDN) for modern web development. In 136 and earlier, a path-traversal flaw in the handling of the X-Zone-Id HTTP header allows an attacker to cause the application to write files outside the intended storage location. The header value is used to build a filesystem path but is not properly canonicalized or restricted to the application’s storage base directory. As a result, supplying ../ sequences in X-Zone-Id causes files to be written to arbitrary directories. Version 136.1 contains a patch.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
Affected products
esm-dev · esm.shpublic PoCs found — 2
exploitdbwww.exploit-db.com/exploits/52461unverifiedgithubgithub.com/byteReaper77/CVE-2025-59342★ 1⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.