CVE-2026-44593esm.sh: Legacy Route Path Traversal Can Lead to RCE
Updated under an hour ago ()
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It affects esm-dev esm.sh. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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esm.sh is a no-build content delivery network (CDN) for web development. In 137 and earlier, the legacy router first retrieves a response from legacyServer, parses the incoming request path, and ultimately writes the data to storage via buildStorage.Put. The router concatenates the path components without sanitizing them, producing a storage key. When this key is used, the underlying file system resolves the relative segments and writes the file to the specified path. Thus an attacker can craft a request that writes data to arbitrary locations on the server.
- CVSS
- 8.7 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-22
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Jun 2, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
esm-dev esm.sh esm_dev:esm.sh (from the name) | through 137 | CNA record |
References
- https://github.com/esm-dev/esm.sh/security/advisories/GHSA-3636-h3vx-6465x-refsource-confirm
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.