How severe is CVE-2021-21796?

CVE-2021-21796 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-2021-21796 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-2021-21796?

CVE-2021-21796 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-2021-21796?

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-2021-21796 published?

CVE-2021-21796 was published on 2021-10-18 and last updated on 2026-06-17.

CVE-2021-21796

CVE-2021-21796 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-416.

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-416
Affected product: Gonitro Nitro Pro
Published: 2021-10-18
Last modified: 2026-06-17

Description

An exploitable use-after-free vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially crafted document can cause an object containing the path to a document to be destroyed and then later reused, resulting in a use-after-free vulnerability, which can lead to code execution under the context of the application. An attacker can convince a user to open a document to trigger this vulnerability.

Frequently asked questions

What is CVE-2021-21796?: An exploitable use-after-free vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially crafted document can cause an object containing the path to a document to be destroyed and then later reused, resulting in a use-after-free vulnerability, which can lead to code execution under the context of the application. An attacker can convince a user to open a document to trigger this vulnerability.
How severe is CVE-2021-21796?: CVE-2021-21796 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-2021-21796 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-2021-21796?: CVE-2021-21796 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-2021-21796?: 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-2021-21796 published?: CVE-2021-21796 was published on 2021-10-18 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1265

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-416 (Use After Free) vulnerabilities

CVE-2026-13782 — Critical (CVSS 10.0): Use after free in Browser in Google Chrome prior to 150.0.7871.47 allowed a remote attacker who had compromised the…
CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
CVE-2025-24085 — Critical (CVSS 10.0): A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.3 and iPadOS 18.3,…
CVE-2024-43102 — Critical (CVSS 10.0): Concurrent removals of certain anonymous shared memory mappings by using the UMTX_SHM_DESTROY sub-request of…
CVE-2021-32495 — Critical (CVSS 10.0): Radare2 has a use-after-free vulnerability in pyc parser's get_none_object function. Attacker can read freed memory…

Browse all CWE-416 (Use After Free) vulnerabilities →