OneDev: RCE through absolute-path symlink following allows low-privileged users to overwrite arbitrary server via TarUtils.untar

published 2026-06-18 4 mo ago modified 2026-10-26 14 d ago also EUVD-2026-37942

cvss: 8.3; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits: 0; none known

OneDev is a Git server with CI/CD, kanban, and packages. In versions 15.0.6 and below, TarUtils.untar() creates symbolic links verbatim from TAR entry getLinkName() without validating whether the target is an absolute path. A subsequent file entry in the same archive traverses the symlink, writing to arbitrary server-side locations. This is exploitable by any authenticated user with CI Job write access — no admin interaction required. This is an incomplete fix bypass of CVE-2021-21251 (GHSA-2w6j-wc8c-9mq2): that patch blocked .. path segments but did not address absolute symlink targets. This issue has been fixed in version 15.0.7.

Patch / fix

links 1

github.com/theonedev/onedev@4f8684a commit

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 4 mo ago (2026-06-22)

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N
CNA	4.0	8.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

theonedev onedev

Classification

Weakness

CWE-61 UNIX Symbolic Link (Symlink) Following

References

Sources

CVE List CVE-2026-49248
NVD CVE-2026-49248

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary