CVE-2021-33793: Foxit Reader before 10.1.4 and PhantomPDF before 10.1.4 have an out-of-bounds write because the Cross-Referenc

Q: How do I fix CVE-2021-33793?

foxit reader: upgrade to 10.1.4; phantompdf: upgrade to 10.1.4. Exact commands for each OS are on this page.

Q: Is CVE-2021-33793 being exploited?

CVE-2021-33793 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-33793 affect?

CVE-2021-33793 affects foxit reader, phantompdf. Severity is critical (CVSS 9.8). Foxit Reader before 10.1.4 and PhantomPDF before 10.1.4 have an out-of-bounds write because the Cross-Reference table is mishandled during Office document conversion.

Q: How urgent is CVE-2021-33793?

Priority 56/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADEUPGRADE

CVE-2021-33793 is a critical-severity flaw (CVSS 9.8) affecting foxit reader, phantompdf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Foxit Reader before 10.1.4 and PhantomPDF before 10.1.4 have an out-of-bounds write because the Cross-Reference table is mishandled during Office document conversion.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 35%)
CISA exploited list	No
Weakness	CWE-787
Published	2021-08-11
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: foxitsoftware

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-08-11 20:15 UTCPublished CVE record published
2026-06-17 03:55 UTCUpdated Record last modified

foxitsoftware foxit reader UPGRADE

Affected: < 10.1.4

Fixed in: 10.1.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy foxit-reader || rpm -q foxit-reader || foxit-reader --version

2. UPGRADE to 10.1.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade foxit-reader

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade foxit-reader

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

foxitsoftware phantompdf UPGRADE

Affected: < 10.1.4

Fixed in: 10.1.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy phantompdf || rpm -q phantompdf || phantompdf --version

2. UPGRADE to 10.1.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade phantompdf

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade phantompdf

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-33793?

foxit reader: upgrade to 10.1.4; phantompdf: upgrade to 10.1.4. Exact commands for each OS are on this page.

Is CVE-2021-33793 being exploited?

CVE-2021-33793 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-33793 affect?

CVE-2021-33793 affects foxit reader, phantompdf. Severity is critical (CVSS 9.8). Foxit Reader before 10.1.4 and PhantomPDF before 10.1.4 have an out-of-bounds write because the Cross-Reference table is mishandled during Office document conversion.

How urgent is CVE-2021-33793?

Priority 56/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2022-43310 HIGH 7.8 UPGRADE An Uncontrolled Search Path Element in Foxit Software released Foxit Reader v11.2.118.51569 allows attackers t
CVE-2021-38574 CRITICAL 9.8 UPGRADE UPGRADE An issue was discovered in Foxit Reader and PhantomPDF before 10.1.4
CVE-2021-38573 CRITICAL 9.8 UPGRADE UPGRADE An issue was discovered in Foxit Reader and PhantomPDF before 10.1.4
CVE-2021-38572 CRITICAL 9.8 UPGRADE UPGRADE An issue was discovered in Foxit Reader and PhantomPDF before 10.1.4
CVE-2021-38571 HIGH 7.8 UPGRADE UPGRADE An issue was discovered in Foxit Reader and PhantomPDF before 10.1.4

References

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