CVE-2018-18688

Name: CVE-2018-18688
Creator: NVD / NIST
Published: 2021-01-07T18:15:12.497+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 1.13%

Last modified Jun 17, 2026

CVE-2018-18688 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. The Portable Document Format (PDF) specification does not provide any information regarding the concrete procedure of how to validate signatures. Consequently, an Incremental Saving vulnerability exists in multiple products. EPSS estimates a 1.13% chance of exploitation in the next 30 days.

Description

The Portable Document Format (PDF) specification does not provide any information regarding the concrete procedure of how to validate signatures. Consequently, an Incremental Saving vulnerability exists in multiple products. When an attacker uses the Incremental Saving feature to add pages or annotations, Body Updates are displayed to the user without any action by the signature-validation logic. This affects Foxit Reader before 9.4 and PhantomPDF before 8.3.9 and 9.x before 9.4. It also affects LibreOffice, Master PDF Editor, Nitro Pro, Nitro Reader, Nuance Power PDF Standard, PDF Editor 6 Pro, PDFelement6 Pro, PDF Studio Viewer 2018, PDF Studio Pro, Perfect PDF 10 Premium, and Perfect PDF Reader.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

1.13%

62.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-347

Affected Software

Vendor	Product	Versions
Code-Industry	Master Pdf Editor	5.1.12
Code-Industry	Master Pdf Editor	5.1.68
Foxitsoftware	Foxit Reader	9.4
Foxitsoftware	Phantompdf	>= 9.0, < 9.4
Foxitsoftware	Phantompdf	8.3.9
Gonitro	Nitro Pro	11.0.3.173
Gonitro	Nitro Reader	5.5.9.2
Iskysoft	Pdf Editor 6	6.4.2.3521
Iskysoft	Pdfelement6	6.8.0.3523
Iskysoft	Pdfelement6	6.8.4.3921
Libreoffice	Libreoffice	6.0.6.2
Libreoffice	Libreoffice	6.1.3.2
Nuance	Power Pdf Standard	3.0.0.17
Nuance	Power Pdf Standard	3.0.0.30
Nuance	Power Pdf Standard	7.0
Qoppa	Pdf Studio	12.0.7
Qoppa	Pdf Studio Viewer 2018	2018.0.1
Qoppa	Pdf Studio Viewer 2018	2018.2.0
Soft-Xpansion	Perfect Pdf 10	10.0.0.1
Soft-Xpansion	Perfect Pdf Reader	13.0.3
Soft-Xpansion	Perfect Pdf Reader	13.1.5
Foxitsoftware	Foxit Reader	9.1.0
Foxitsoftware	Foxit Reader	9.2.0
Code-Industry	Master Pdf Editor	5.1.24
Iskysoft	Pdf Editor 6	6.6.2.3315
Iskysoft	Pdf Editor 6	6.7.6.3399
Iskysoft	Pdfelement6	6.7.1.3355
Iskysoft	Pdfelement6	6.7.6.3399
Libreoffice	Libreoffice	6.1.0.3

References

https://pdf-insecurity.org/signature/evaluation_2018.htmlThird Party Advisory
https://pdf-insecurity.org/signature/signature.htmlThird Party Advisory
https://www.foxitsoftware.com/support/security-bulletins.phpVendor Advisory
https://www.pdfa.org/recently-identified-pdf-digital-signature-vulnerabilities/Third Party Advisory
https://pdf-insecurity.org/signature/evaluation_2018.htmlThird Party Advisory
https://pdf-insecurity.org/signature/signature.htmlThird Party Advisory
https://www.foxitsoftware.com/support/security-bulletins.phpVendor Advisory
https://www.pdfa.org/recently-identified-pdf-digital-signature-vulnerabilities/Third Party Advisory

Timeline

Published: Jan 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2018-18688?

How severe is CVE-2018-18688?

CVE-2018-18688 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 1.13% probability of exploitation in the next 30 days.

How do I fix CVE-2018-18688?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2018-18688?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST