ProjectDiscovery Nuclei 3 before 3.8.0 allows DSL expression injection. This affects use of -env-vars for multi-step templates against untrusted targets (not the default configuration).

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

ProjectDiscovery Nuclei 3 before 3.8.0 allows DSL expression injection. This affects use of -env-vars for multi-step templates against untrusted targets (not the default configuration).

Source published

20 Apr 2026 07:10:30 UTC

Source modified

21 Apr 2026 00:59:19 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 4.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N

Nuclei is a vulnerability scanner built on a simple YAML-based DSL. From version 3.0.0 to before version 3.8.0, a vulnerability in Nuclei's expression evaluation engine makes it possible for a malicious target server to inject and execute supported DSL expressions. This happens when HTTP response data containing helper/function syntax gets reused by multi-step templates. If the -env-vars / -ev option is explicitly enabled, this can expose host environment variables. That option is off by default, so standard configurations are not affected by the information disclosure risk. This issue has been patched in version 3.8.0.

Source published

8 May 2026 03:17:19 UTC

Source modified

11 May 2026 18:16:02 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

ProjectDiscovery Nuclei 3 before 3.8.0 allows DSL expression injection. This affects use of -env-vars for multi-step templates against untrusted targets (not the default configuration).

Source published

Apr 20, 2026, 7:10:30 AM (timezone not stated)

Source modified

Apr 21, 2026, 12:59:19 AM (timezone not stated)

Observed here

28 Oct 2026 05:07:45 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 4.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N

Nuclei is a vulnerability scanner built on a simple YAML-based DSL. From version 3.0.0 to before version 3.8.0, a vulnerability in Nuclei's expression evaluation engine makes it possible for a malicious target server to inject and execute supported DSL expressions. This happens when HTTP response data containing helper/function syntax gets reused by multi-step templates. If the -env-vars / -ev option is explicitly enabled, this can expose host environment variables. That option is off by default, so standard configurations are not affected by the information disclosure risk. This issue has been patched in version 3.8.0.

Source published

May 8, 2026, 3:17:19 AM (timezone not stated)

Source modified

May 11, 2026, 6:16:02 PM (timezone not stated)

Observed here

28 Oct 2026 05:10:33 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

ProjectDiscovery Nuclei 3 before 3.8.0 allows DSL expression injection. This affects use of -env-vars for multi-step templates against untrusted targets (not the default configuration).

Source published

20 Apr 2026 08:16:10 UTC

Source modified

26 Oct 2026 21:10:00 UTC

Observed here

27 Oct 2026 10:10:11 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 4.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N

CVSS 3.1 · [email protected] · Primary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Nuclei is a vulnerability scanner built on a simple YAML-based DSL. From version 3.0.0 to before version 3.8.0, a vulnerability in Nuclei's expression evaluation engine makes it possible for a malicious target server to inject and execute supported DSL expressions. This happens when HTTP response data containing helper/function syntax gets reused by multi-step templates. If the -env-vars / -ev option is explicitly enabled, this can expose host environment variables. That option is off by default, so standard configurations are not affected by the information disclosure risk. This issue has been patched in version 3.8.0.

Source published

8 May 2026 04:16:18 UTC

Source modified

26 Oct 2026 20:10:00 UTC

Observed here

27 Oct 2026 10:10:19 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

A vulnerability in Nuclei's expression evaluation engine makes it possible for a malicious target server to inject and execute supported DSL expressions. This happens when HTTP response data containing helper/function syntax gets reused by multi-step templates. If the `-env-vars` / `-ev` option is explicitly enabled, this can expose host environment variables. That option is off by default, so standard configurations are not affected by the information disclosure risk. **Affected Component** The issue lives in `expressions.Evaluate()` at `pkg/protocols/common/expressions/` and in the unresolved-variable validation path (`hasLiteralsOnly()`). **Description** `expressions.Evaluate()` replaces placeholders first, then scans the substituted output for expressions. Because of this two-pass approach, response-derived values (including extractor output and response body content) can be reinterpreted as DSL/helper syntax on the second pass. When `-env-vars` (`-ev`) is enabled, environment variables get merged into the template variable map. A malicious target can return response data containing expressions like `{{env_var_name}}` which, when reused in a subsequent template request, resolve to actual environment variable values. This can expose sensitive host data like API keys, credentials, and tokens. Without `-ev` enabled (the default), injected DSL expressions may still trigger helper functions such as `{{md5("test")}}`, but this has no meaningful security impact beyond unexpected behavior. There is also a separate issue in `hasLiteralsOnly()`: it was evaluating helper expressions while deciding whether `{{...}}` contained unresolved variables, which caused validation logic to run side-effectful helpers even when the final request kept the value as a literal. > [!NOTE] The `-env-vars` / `-ev` option is off by default. Users who have not explicitly turned it on are not affected by the information disclosure aspect of this vulnerability. **Affected Users** - **CLI users** running multi-step templates (with extractors or flow-based request chaining) that reuse response-derived values against untrusted or attacker-controlled targets, with the `-ev` flag enabled. - **SDK users** who have integrated Nuclei into platforms where `EnvironmentVariables` is set to `true` and scan targets are not fully trusted. **Patches** - The vulnerability is fixed in Nuclei v3.8.0. Upgrading to this version is strongly recommended. - Relevant fix references: #7221, #7321. **Mitigation** Upgrade to Nuclei v3.8.0. The updated evaluation logic now collects expressions from the original template text before placeholder substitution and only evaluates those template-authored expressions. If you have `-ev` enabled, disable it when scanning untrusted targets to avoid environment variable disclosure. **Workarounds** If upgrading is not an option right now, make sure `-env-vars` / `-ev` is not enabled when running multi-step templates against untrusted targets. **Acknowledgments** Nuclei thanks @gnuletik for reporting this issue through responsible disclosure via [email protected]

Source published

22 Apr 2026 19:59:14 UTC

Source modified

8 Jul 2026 08:26:19 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

Publisher rating · MODERATE

Nuclei: Environment variable disclosure via Response-Derived DSL Expressions in github.com/projectdiscovery/nuclei

Source published

25 Jun 2026 22:34:31 UTC

Source modified

8 Jul 2026 08:26:19 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.