CVE-2023-33866: Foxit Reader · Use After Free
Affects Foxit ReaderSource CVE Database V5
Not known to be exploited · CVSS 8.8 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.9% chance of exploitation in 30 days – higher than 60% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Foxit Foxit Reader | Affected
| Fixed in– |
AI-suggested
- Immediately disable the Foxit Reader browser plugin to prevent exploitation via malicious websites.
- Advise users to avoid opening PDF files from untrusted or unknown sources until a patch is available.
- Implement network-level protections such as email filtering and web content scanning to detect and block malicious PDFs.
- Monitor for suspicious process behavior or unexpected Foxit Reader activity indicative of exploitation attempts.
- Employ application whitelisting and endpoint detection and response (EDR) solutions to detect and prevent arbitrary code execution.
- Once Foxit releases a security patch, prioritize deployment across all affected systems.
- Educate users about the risks of opening unsolicited PDFs and visiting untrusted websites.
- Consider alternative PDF readers with a better security posture temporarily if patching is delayed.
- Restrict the use of Foxit Reader to only trusted environments or sandbox its execution to limit potential damage.
- Maintain up-to-date backups to enable recovery in case of compromise.
Description
A use-after-free vulnerability exists in the JavaScript engine of Foxit Software’s PDF Reader, version 12.1.2.15332. By prematurely deleting objects associated with pages, a specially crafted PDF document can trigger the reuse of previously freed memory, which can lead to arbitrary code execution. An attacker needs to trick the user into opening the malicious file to trigger this vulnerability. Exploitation is also possible if a user visits a specially crafted, malicious site if the browser plugin extension is enabled.