BLT: Improper Control of Generation of Code
CVE-2026-40316 is a high-severity improper control of generation of code vulnerability in BLT from OWASP-BLT, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected BLT versions: <= 2.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of BLT you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| OWASP-BLT | BLT | <= 2.1 | Not stated |
| Owasp | Owasp Blt | 2.1 and earlier | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (github.com).
Official description
OWASP BLT is a QA testing and vulnerability disclosure platform that encompasses websites, apps, git repositories, and more. Versions prior to 2.1.1 contain an RCE vulnerability in the .github/workflows/regenerate-migrations.yml workflow. The workflow uses the pull_request_target trigger to run with full GITHUB_TOKEN write permissions, copies attacker-controlled files from untrusted pull requests into the trusted runner workspace via git show, and then executes python manage.py makemigrations, which imports Django model modules including attacker-controlled website/models.py at runtime. Any module-level Python code in the attacker's models.py is executed during import, enabling arbitrary code execution in the privileged CI environment with access to GITHUB_TOKEN and repository secrets. The attack is triggerable by any external contributor who can open a pull request, provided a maintainer applies the regenerate-migrations label, potentially leading to secret exfiltration, repository compromise, and supply chain attacks. A patch for this issue is expected to be released in version 2.1.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Control of Generation of Code
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.
How developers prevent this class of flaw
- Refactor your program so that you do not have to dynamically generate code.
- Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
More Improper Control of Generation of Code vulnerabilities (CWE-94)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in BLT
- 8.8 High severity
Recent Improper Control of Generation of Code vulnerabilities
- 9.9 Critical severity
- 8.1 High severity
- 8.4 High severity
- 7.4 High severity
- 8.8 High severity
- 7.8 High severity
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