CVE-2026-74788 Scriban before 7.0.0 Denial of Service via string.pad_left/pad_right

What is CVE-2026-74788?

CVE-2026-74788 is a high-severity denial of service vulnerability in scriban, published on 16 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Scriban before 7.0.0 (affected versions <= 6.6.0) contains an uncontrolled memory allocation vulnerability in the string.pad_left and string.pad_right template functions, which perform no validation on the width parameter before delegating to .NET's String.PadLeft/PadRight. When an application exposes Scriban to untrusted template input, an attacker can supply an arbitrarily large width value (e.g., 500,000,000) to trigger ~1GB memory allocations in a single call, resulting in OutOfMemoryException and denial of service. The TemplateContext.LimitToString limit does not prevent this because it is only enforced after the string has been fully allocated.

Weakness: CWE-770

Which versions are affected by CVE-2026-74788?

4 open source packages ship an affected version, including Scriban and Scriban.Signed.

How do I fix CVE-2026-74788?

Upgrade Scriban to 7.0.0 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-74788 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-74788 exists.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• GitHub advisory
• How this page is made

Also known as GHSA-3qxv-x8gq-wgff, GHSA-v66j-x4hw-fv9g.