qbee transport: Symlink-chain path traversal in tar extraction (one level outside destination)

published 2026-06-19 4 mo ago modified 2026-09-30 39 d ago also GHSA-f9m7-vc86-p6jj , GO-2026-5352 , EUVD-2026-78783

cvss: 6.0; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits: 0; none known

qbee transport is a remote access transport protocol implementation. Prior to 1.26.25, the extractTar routine uses strictly lexical path validation that does not account for on-disk symlinks created earlier in the extraction process. A crafted tar archive can use a symlink chain to write or overwrite files one directory level above the intended extraction path. When qbee-agent performs the extraction with root privileges, this permits a root-privileged file write outside the intended destination. This issue is fixed in version 1.26.25.

Patch / fix

fixed in 1 distros 1 links 2

go go.qbee.io/transport 1.26.25

govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

github.com/qbee-io/transport@4394767 commit
github.com/qbee-io/transport#19 pull request

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 54 d ago (2026-09-15)

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.0	CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
CNA	4.0	6.0	CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/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 packages

ecosystem	package	affected	fixed in
go	go.qbee.io/transport	<1.26.25	1.26.25

Affected products

qbee-io transport

Classification

Weakness

CWE-22 Improper Limitation of a Pathname to a Restricted Directory
CWE-59 Improper Link Resolution Before File Access

References

Sources

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