CVE-2023-33876VulnerabilityPublished 19 Jul 2023Updated 4 Nov 2025

CVE-2023-33876: 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, 06:26 UTC

CVSS 3.1 base score

8.8High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.9% chance of exploitation in 30 days – higher than 61% 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:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation 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 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Foxit Foxit Reader	Affected =12.1.2.15332	Fixed in–

AI-suggested

1. Immediately disable JavaScript execution within Foxit Reader settings to prevent malicious script execution embedded in PDFs. 2. Disable or uninstall the Foxit Reader browser plugin to eliminate drive-by attack vectors from malicious websites. 3. Monitor for and apply official patches from Foxit as soon as they are released; maintain close contact with vendor advisories. 4. Implement email filtering and sandboxing to detect and block malicious PDF attachments before reaching end users. 5. Conduct user awareness training focused on the risks of opening unsolicited or suspicious PDF files. 6. Employ endpoint detection and response (EDR) solutions to identify anomalous behaviors indicative of exploitation attempts. 7. Restrict Foxit Reader usage to trusted users or environments where possible, and consider alternative PDF readers with a reduced attack surface. 8. Regularly audit installed software versions across the organization to identify and remediate vulnerable instances promptly.

Description

A use-after-free vulnerability exists in the way Foxit Reader 12.1.2.15332 handles destroying annotations. Specially crafted Javascript code inside a malicious PDF document can trigger reuse of a previously freed object, which can lead to memory corruption and result in 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.

Impact

For European organizations, this vulnerability poses a significant risk due to the widespread use of Foxit Reader in business, government, and critical infrastructure sectors. Successful exploitation could lead to arbitrary code execution, enabling attackers to gain control over affected systems, steal sensitive data, disrupt operations, or deploy ransomware. The requirement for user interaction limits mass exploitation but targeted phishing campaigns or watering hole attacks could be effective. Organizations relying on Foxit Reader's browser plugin are at increased risk as drive-by attacks become possible. Confidentiality, integrity, and availability of systems and data can be severely impacted, potentially affecting regulatory compliance (e.g., GDPR) and operational continuity. The absence of known exploits in the wild provides a window for proactive mitigation before widespread attacks emerge.

CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2025, 20:31 UTC

WeaknessesCWE-416

Technical details

References

Community reviews

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