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Code Injection via TStreamerInfo Metadata

High
ariostas published GHSA-6946-mq52-g438 Jul 20, 2026

Package

pip uproot (pip)

Affected versions

<=5.7.4

Patched versions

5.7.5

Description

Uproot dynamically generates Python class source from ROOT TStreamerInfo records and compiles it at runtime. Some file-controlled streamer metadata fields are interpolated into generated Python source without safe quoting, such as repr() / !r.

An attacker who can provide a crafted ROOT file can place Python expression-breaking content into streamer metadata, such as a crafted element name. When uproot generates and invokes the corresponding reader method, the injected Python expression executes in the context of the process using uproot.

Impact

Arbitrary Python code execution in applications that open or process attacker-controlled ROOT files with affected uproot code paths.

Patches

Uproot v5.7.5 contains the patch.

Users of packages that depend on Uproot, such as Coffea, should update Uproot too.

References

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVE ID

CVE-2026-9147

Weaknesses

Improper Control of Generation of Code ('Code Injection')

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Learn more on MITRE.

Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. eval). Learn more on MITRE.

Credits