How severe is CVE-2021-26120?

CVE-2021-26120 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-26120 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 82% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26120?

CVE-2021-26120 primarily affects Smarty. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-26120?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-26120 published?

CVE-2021-26120 was published on 2021-02-22 and last updated on 2026-06-17.

CVE-2021-26120

CVE-2021-26120 is a critical-severity vulnerability in Smarty with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 82% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-94.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 82% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-94
Affected product: Smarty
Published: 2021-02-22
Last modified: 2026-06-17

Description

Smarty before 3.1.39 allows code injection via an unexpected function name after a {function name= substring.

Frequently asked questions

What is CVE-2021-26120?: Smarty before 3.1.39 allows code injection via an unexpected function name after a {function name= substring.
How severe is CVE-2021-26120?: CVE-2021-26120 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-26120 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 82% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26120?: CVE-2021-26120 primarily affects Smarty. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-26120?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-26120 published?: CVE-2021-26120 was published on 2021-02-22 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:smarty:smarty:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

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