CVE-2025-6518 PySpur-Dev pyspur Jinja2 Template single_llm_call.py SingleLLMCallNode special elements used in a template engine
Remote attackers can execute arbitrary code via Jinja2 template injection in the SingleLLMCallNode user_message argument.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-6518?
CVE-2025-6518 is a medium-severity code injection vulnerability in PySpur-Dev pyspur, published on 23 Jun 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability was found in PySpur-Dev pyspur up to 0.1.18. It has been classified as critical. Affected is the function SingleLLMCallNode of the file backend/pyspur/nodes/llm/single_llm_call.py of the component Jinja2 Template Handler. The manipulation of the argument user_message leads to improper neutralization of special elements used in a template engine. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.
Which versions are affected by CVE-2025-6518?
3 open source packages ship an affected version, including pyspur.
| Package | Affected | Fixed in |
|---|---|---|
pyspur PyPI | All versions to 0.1.18 | None |
pyspur PyPI | All versions to 0.1.18 | None |
pyspur PyPI | All versions to 0.1.18 | None |
How do I fix CVE-2025-6518?
No fix has been published for CVE-2025-6518 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2025-6518 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-6518 exists.
Sources
Also known as GHSA-8gff-cf92-72pv, PYSEC-2026-1844.