gonic has arbitrary file write in createPlaylist: any authenticated user can write playlist M3U content to attacker-controlled path on the host

published 2026-06-19 4 mo ago modified 2026-10-25 14 d ago also GHSA-4gxv-p5g5-j7w7 , GO-2026-5827 , EUVD-2026-38068

cvss: 8.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits: 0; none known

gonic is a music streaming server / free-software subsonic server API implementation. Prior to version 0.21.0, a logic error in `ServeCreateOrUpdatePlaylist` allows any authenticated Subsonic user (including non-admin) to write playlist M3U content to an attacker-controlled absolute filesystem path on the gonic host, and to create intermediate directories with `0o777` permissions. The bug is independent of CVE-2026-49338 and CVE-2026-49339. It is an unreachable guard clause combined with no path containment in `Store.Write`. Version 0.21.0 patches the issue.

Patch / fix

fixed in 1 distros 1

go go.senan.xyz/gonic 0.21.0

govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 4 mo ago (2026-06-22)

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/sentriz/gonic/security/advisories/GHSA-4gxv-p5g5-j7w7 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
GitHub	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
go	go.senan.xyz/gonic	<0.21.0	0.21.0

Affected products

sentriz gonic

Classification

Weakness

CWE-22 Improper Limitation of a Pathname to a Restricted Directory
CWE-697 Incorrect Comparison
CWE-732 Incorrect Permission Assignment for Critical Resource

References

github.com /sentriz/gonic/security/advisories/GHSA-4gxv-p5g5-j7w7
exploit, web, advisory
nvd.nist.gov /vuln/detail/CVE-2026-49340
advisory
github.com /sentriz/gonic
package

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