SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-21796

An exploitable use-after-free vulnerability exists in the JavaScript implementation of Nitro Pro PDF.

HIGH 7.8EPSS 15.8%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 15.8%, higher than 97% of all known CVEs. Patch or mitigate before the next change window.

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.

CVSS 3.1
7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
15.78% probability · 97th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-416
Affected
gonitro/nitro pro
Source
talos-cna@cisco.com
EPSS trend
0%10%20%3 November 2026: 15.78%3 November 20263 November 2026

EPSS 15.8% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.