GHSA-462w-v97r-4m45 — high GitHub Advisory (CVE-2019-10906) in pip/Jinja2

Description

In Pallets Jinja before 2.10.1, str.format_map allows a sandbox escape.

The sandbox is used to restrict what code can be evaluated when rendering untrusted, user-provided templates. Due to the way string formatting works in Python, the str.format_map method could be used to escape the sandbox.

This issue was previously addressed for the str.format method in Jinja 2.8.1, which discusses the issue in detail. However, the less-common str.format_map method was overlooked. This release applies the same sandboxing to both methods.

If you cannot upgrade Jinja, you can override the is_safe_attribute method on the sandbox and explicitly disallow the format_map method on string objects.

Basic information

Type: reviewed
Severity: high
Advisory on GitHub: Open advisory ↗
Repository advisory: —
Source code: Browse source ↗
Published (advisory): 2019-04-10 14:30:24 UTC
Updated: 2024-09-24 20:49:57 UTC
GitHub reviewed: 2020-06-16 20:57:35 UTC
NVD published: 2019-04-06

Score	Percentile
3.48%	87.50%

CVSS Scores

Base score	Version	Severity	Vector
8.6	3.0	—	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.
7.7	4.0	—	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network. Attack complexity (AC:L) Exploitation conditions are straightforward and stable. Attack requirements (AT:N) No additional preconditions are required beyond normal reachability. Privileges required (PR:N) No privileges are required. User interaction (UI:N) No user interaction is required. Vulnerable system confidentiality impact (VC:N) No confidentiality impact on the vulnerable system. Vulnerable system integrity impact (VI:N) No integrity impact on the vulnerable system. Vulnerable system availability impact (VA:N) No availability impact on the vulnerable system. Subsequent system confidentiality impact (SC:H) High confidentiality impact on subsequent systems. Subsequent system integrity impact (SI:N) No integrity impact on subsequent systems. Subsequent system availability impact (SA:N) No availability impact on subsequent systems.

Identifiers

Type	Value
GHSA	GHSA-462w-v97r-4m45 ↗
CVE	CVE-2019-10906 ↗

CWEs

CWE id	Name
CWE-693	Protection Mechanism Failure

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem	Package	Vulnerable range	First patched	Vulnerable functions
pip	Jinja2	< 2.10.1	2.10.1	—

Jinja2 sandbox escape via string formatting