Summary
rclone archive/zip: Zip Slip via unsanitized zip entry names lets a malicious archive escape its own namespace
backend/archive mounts a zip file as a browsable, syncable rclone Fs (e.g. rclone lsf :zip:downloaded.zip or rclone copy :zip:downloaded.zip dest:). Go's archive/zip package does not sanitize file.Name - it is taken verbatim from the untrusted zip's central directory. readZip() in backend/archive/zip/zip.go applies path.Clean to the entry name, but this alone cannot fully neutralize a name with more .. components than real segments preceding them (e.g. "../../etc/cron.d/evil" stays exactly as-is after cleaning). When the archive is mounted with an empty root (the common case), there was no check at all that the resulting name stayed inside the archive's own namespace, so it was stored verbatim and returned unchanged by Object.Remote().
fs/sync/fs/operations use srcObj.Remote() directly as the destination-relative path when copying between filesystems, so a maliciously crafted zip file can cause rclone copy/sync to attempt writes outside the intended destination directory on whatever backend it targets - this is the well-known "Zip Slip" vulnerability class (https://security.snyk.io/research/zip-slip-vulnerability) applied to rclone's own zip-mounting backend. It is distinct from cmd/archive/extract, which already validates via its own destPath() choke point and is not affected.
Details
Vulnerable code (before fix), backend/archive/zip/zip.go, (*Fs).readZip:
for _, file := range zr.File {
remote := strings.Trim(path.Clean(file.Name), "/")
if remote == "." { remote = "" }
remote = path.Join(f.prefix, remote)
if f.root != "" {
// Ignore all files outside the root
if !strings.HasPrefix(remote, f.root) { continue }
...
}
...
o := &Object{f: f, remote: remote, ...}
dt.Add(o)
}
The escape check only ran when f.root != "", and even then used a bare strings.HasPrefix with no boundary check (so f.root="foo" incorrectly also matched a sibling entry "foobar").
PoC
Built a zip in memory with Go's real archive/zip writer (entry name "../../etc/cron.d/evil", not sanitized by the writer either), wrote it to disk, and mounted it via the actual production constructor zip.New(ctx, localFs, "evil.zip", "", ""):
zip entry Name="../../etc/cron.d/evil" -> Object.Remote()="../../etc/cron.d/evil"
Fully outside the archive's own namespace - confirmed via a regression test that mounts the malicious zip through the real local backend and inspects the resulting Fs's internal dirtree and every Object's Remote().
Impact
A user who runs rclone copy/sync/mount against an untrusted zip file (downloaded, e-mailed, etc.) can have files written outside the intended destination directory on the destination backend, depending on that backend's own confinement. No server compromise or custom remote configuration is required from the attacker - only a crafted zip file and a normal rclone copy/sync invocation by the victim.
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-88014 has a CVSS score of 6.3 (Medium). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.75.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Skip any zip entry whose cleaned+prefixed name still escapes the archive's own namespace, rather than exposing it. Also tightened the pre-existing root filter's weak prefix check.
Frequently Asked Questions
- What is CVE-2026-88014? CVE-2026-88014 is a medium-severity path traversal vulnerability in github.com/rclone/rclone (go), affecting versions >= 1.72.0, < 1.75.1. It is fixed in 1.75.1. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-88014? CVE-2026-88014 has a CVSS score of 6.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/rclone/rclone are affected by CVE-2026-88014? github.com/rclone/rclone (go) versions >= 1.72.0, < 1.75.1 is affected.
- Is there a fix for CVE-2026-88014? Yes. CVE-2026-88014 is fixed in 1.75.1. Upgrade to this version or later.
- Is CVE-2026-88014 exploitable, and should I be worried? Whether CVE-2026-88014 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-88014 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-88014? Upgrade
github.com/rclone/rcloneto 1.75.1 or later.