CVE-2021-29440

mediumpriority · attend · 49EPSS 0.299 · 98 %ileexploit · PoCEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

2 exploits · PoC

Likely / severe?

29.9% (98th) EPSS

CVSS 6.5 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

Grav is a file based Web-platform. Twig processing of static pages can be enabled in the front matter by any administrative user allowed to create or edit pages. As the Twig processor runs unsandboxed, this behavior can be used to gain arbitrary code execution and elevate privileges on the instance. The issue was addressed in version 1.7.11.

cvss

Technical severity, 0–10. One row per scoring source.

8.4

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–8.4

v2.06.5mediumAV:N/AC:L/Au:S/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8 · impact 6.4

v3.17.2highCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 1.2 · impact 5.9

v3.18.4highCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:Hsecondary · ENISA EU

v3.18.4highCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:Hsecondary · security-advisories@github.comexploitability 1.7 · impact 6

v3.18.4highCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:Hsecondary · OSV

v3.16.8mediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:Psecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-94USCWE-94US

exploits (2)

Public proof-of-concept and weaponised exploit code.

EDB-49961Grav CMS 1.7.10 - Server-Side Template Injection (SSTI) (Authenticated)PoC · exploit_db
CsEnox/CVE-2021-29440Unsafe Twig processing of static pages leading to RCE in Grav CMS 1.7.10PoC · poc_in_github

affected products (3)

Products and version ranges known to be affected.

getgrav grav≤ < 1.7.11enisa_euvdEU
getgrav grav< 1.7.11nvdUScpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:*
Packagist getgrav/grav< 1.7.11osvUSpkg:composer/getgrav/grav

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-g8r4-p96j-xfxcGrav's Twig processing allowing dangerous PHP functions by default2021-04-16ghsa · osvUS
### Impact Twig processing of static pages can be enabled in the front matter by any administrative user allowed to create or edit pages. As the Twig processor runs unsandboxed, this behavior can be used to gain arbitrary code execution and elevate privileges on the instance. ### Patches The issue was addressed by preventing dangerous functions from being called in Twig templates. A configuration option has been added to manually allow arbitrary PHP functions (`system.twig.safe_functions`) and filters (`system.twig.safe_filters`). Futures major versions of Grav may disable this functionality by default. ### Workarounds Blocking access to the `/admin` path from untrusted sources will reduce the probability of exploitation. ### References - https://portswigger.net/research/server-side-template-injection - https://blog.sonarsource.com/grav-cms-code-execution-vulnerabilities ### For more information If you have any questions or comments about this advisory, you can contact: - The original reporters, by sending an email to vulnerability.research [at] sonarsource.com; - The maintainers, by opening an issue on this repository.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2021-04-13modified 2026-06-17

references (16)

External citations — patches, advisories, analysis.

scry

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