wix-incubator jam Jinja2 Template jam.py special elements used in a template engine

published 2025-04-21 18 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-12353

cvss: 3.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

A vulnerability, which was classified as problematic, was found in wix-incubator jam up to e87a6fd85cf8fb5ff37b62b2d68f917219d07ae9. This affects an unknown part of the file jam.py of the component Jinja2 Template Handler. The manipulation of the argument config['template'] leads to improper neutralization of special elements used in a template engine. It is possible to launch the attack on the local host. The exploit has been disclosed to the public and may be used. This product takes the approach of rolling releases to provide continious delivery. Therefore, version details for affected and updated releases are not available.

Patch / fix

fixed in 1

wix jam 2018-03-27

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 18 mo ago (2025-04-21)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/wix-incubator/jam/issues/1 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	4.8	CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CNA	3.1	3.3	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CNA	3.0	3.3	CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CNA	2.0	1.7	AV:L/AC:L/Au:S/C:N/I:P/A:N
CNA	4.0	4.8	CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/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
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

wix-incubator jam

Classification

Weakness

CWE-1336 Improper Neutralization of Special Elements Used in a Template Engine
CWE-791 Incomplete Filtering of Special Elements
CWE-94 Improper Control of Generation of Code

References

github.com /wix-incubator/jam/issues/1
exploit, issue-tracking, vendor-advisory
vuldb.com /?id.305769
vdb-entry, technical-description, third-party-advisory
vuldb.com /?ctiid.305769
signature, permissions-required, vdb-entry
vuldb.com /?submit.555905
third-party-advisory, vdb-entry

Sources

CVE List CVE-2025-3841
NVD CVE-2025-3841

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