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No exploitation reported

CVE-2021-21797

No exploitation reported by the sources we read.

  • Published2021-10-18
  • WeaknessCWE-415

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-10-1813:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-04 09:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-21797?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-21797?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Gonitro nitro pro
BranchAffectedFixed in
13.31= 13.31.0.605no fix published
13.33= 13.33.2.645no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.8read 2026-10-23
  • CNACVSS 3.08.8known since 2026-10-23
  • NVDCVSS 2.06.8read 2026-10-23
  • CNAweakness (CWE)CWE-415known since 2026-10-23
  • NVDweakness (CWE)CWE-415read 2026-10-23
  • FIRST EPSSEPSS score15.0 %read 2026-11-03

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
2021-10-18
Last Modified
2026-06-17
NVD status
Modified

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.

Is CVE-2021-21797 actively exploited?

Active exploitation of CVE-2021-21797 has not been confirmed. Its EPSS score was 15.0% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-21797?

CVE-2021-21797 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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