How severe is CVE-2021-21797?

CVE-2021-21797 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-2021-21797 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 15% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21797?

CVE-2021-21797 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-2021-21797?

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-2021-21797 published?

CVE-2021-21797 was published on 2021-10-18 and last updated on 2026-06-17.

CVE-2021-21797

CVE-2021-21797 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 15% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-415.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 15% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-415
Affected product: Gonitro Nitro Pro
Published: 2021-10-18
Last modified: 2026-06-17

Description

An exploitable double-free vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially crafted document can cause a reference to a timeout object to be stored in two different places. When closed, the document will result in the reference being released twice. This 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-2021-21797?: An exploitable double-free vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially crafted document can cause a reference to a timeout object to be stored in two different places. When closed, the document will result in the reference being released twice. This 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-2021-21797?: CVE-2021-21797 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-2021-21797 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 15% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21797?: CVE-2021-21797 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-2021-21797?: 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-2021-21797 published?: CVE-2021-21797 was published on 2021-10-18 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1266

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-2021-21796 — High (CVSS 7.8): An exploitable use-after-free vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially…

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CVE-2020-37239 — Critical (CVSS 9.8): libbabl 0.1.62 contains a broken double free detection vulnerability that allows attackers to bypass memory safety…
CVE-2026-43011 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: net/x25: Fix potential double free of skb When…
CVE-2026-31609 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid double-free in…
CVE-2026-31608 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: server: avoid double-free in…

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