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Fencer Intel
high 8.8

CVE-2021-21798 in the critical feed json

An exploitable return of stack variable address vulnerability exists in the JavaScript implementation of Nitro Pro PDF.

published 5y ago modified 4mo ago also EUVD-2021-8970

cvss
8.8
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
21.4%
EPSS 21.4% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

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.

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Exploit prediction

21.37% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • talosintelligence.com https://talosintelligence.com/vulnerability_reports/TALOS-2021-1267 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 8.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • n/a Nitro Pro

Classification

Weakness
  • CWE-562 Return of Stack Variable Address

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.