How severe is CVE-2021-21798?

CVE-2021-21798 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-21798 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 16% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21798?

CVE-2021-21798 primarily affects Gonitro Nitro Pro. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-21798?

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

When was CVE-2021-21798 published?

CVE-2021-21798 was published on 2021-09-15 and last updated on 2026-06-17.

CVE-2021-21798

CVE-2021-21798 is a high-severity vulnerability in Gonitro Nitro Pro with a CVSS 3.x base score of 7.8. Its EPSS exploit-prediction score of 16% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-562.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 16% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-562
Affected product: Gonitro Nitro Pro
Published: 2021-09-15
Last modified: 2026-06-17

Description

An exploitable return of stack variable address vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially crafted document can cause a stack variable to go out of scope, resulting in the application dereferencing a stale pointer. This can lead to code execution under the context of the application. An attacker can convince a user to open a document to trigger the vulnerability.

Frequently asked questions

What is CVE-2021-21798?: An exploitable return of stack variable address vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially crafted document can cause a stack variable to go out of scope, resulting in the application dereferencing a stale pointer. This can lead to code execution under the context of the application. An attacker can convince a user to open a document to trigger the vulnerability.
How severe is CVE-2021-21798?: CVE-2021-21798 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-21798 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 16% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21798?: CVE-2021-21798 primarily affects Gonitro Nitro Pro. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21798?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-21798 published?: CVE-2021-21798 was published on 2021-09-15 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1267

Affected products (2)

cpe:2.3:a:gonitro:nitro_pro:13.31.0.605:*:*:*:*:*:*:*
cpe:2.3:a:gonitro:nitro_pro:13.33.2.645:*:*:*:*:*:*:*

More vulnerabilities in Gonitro Nitro Pro

CVE-2020-6146 — High (CVSS 8.8): An exploitable code execution vulnerability exists in the rendering functionality of Nitro Pro 13.13.2.242 and…
CVE-2020-6074 — High (CVSS 8.8): An exploitable code execution vulnerability exists in the PDF parser of Nitro Pro 13.9.1.155. A specially crafted PDF…
CVE-2017-7442 — High (CVSS 8.8): Nitro Pro 11.0.3.173 allows remote attackers to execute arbitrary code via saveAs and launchURL calls with directory…
CVE-2020-10223 — High (CVSS 8.1): npdf.dll in Nitro Pro before 13.13.2.242 is vulnerable to JBIG2Decode CNxJBIG2DecodeStream Heap Corruption at…
CVE-2020-10222 — High (CVSS 8.1): npdf.dll in Nitro Pro before 13.13.2.242 is vulnerable to Heap Corruption at npdf!nitro::get_property+2381 via a…
CVE-2021-21797 — High (CVSS 7.8): An exploitable double-free vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially crafted…

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Other CWE-562 vulnerabilities

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CVE-2020-21686 — Medium (CVSS 5.5): A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows…
CVE-2026-26399 — Medium (CVSS 5.3): A stack-use-after-return issue exists in the Arduino_Core_STM32 library prior to version 1.7.0. The pwm_start()…
CVE-2026-34553 — Medium (CVSS 4.0): iccDEV provides a set of libraries and tools for working with ICC color management profiles. Prior to version 2.3.1.6,…

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