CVE-2026-91817: A heap-based out-of-bounds read vulnerability exists in Foxit PDF Editor/Reader’s handling of wide strings in

Q: How do I fix CVE-2026-91817?

pdf editor: upgrade to newer than 2026.2.0.39747; pdf reader: upgrade to newer than 2026.2.0.39747. Exact commands for each OS are on this page.

Q: Is CVE-2026-91817 being exploited?

CVE-2026-91817 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-2026-91817 affect?

CVE-2026-91817 affects pdf editor, pdf reader. Severity is medium (CVSS 6.1). A heap-based out-of-bounds read vulnerability exists in Foxit PDF Editor/Reader’s handling of wide strings in embedded PDF JavaScript. Insufficient validation of string-deletion ranges can cause an integer underflow, resulting in an out-of-

Q: How urgent is CVE-2026-91817?

Priority 22/100. No elevated risk signals yet.

Routine

MEDIUM 6.1UPGRADEUPGRADE

CVE-2026-91817 is a medium-severity flaw (CVSS 6.1) affecting pdf editor, pdf reader. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A heap-based out-of-bounds read vulnerability exists in Foxit PDF Editor/Reader’s handling of wide strings in embedded PDF JavaScript. Insufficient validation of string-deletion ranges can cause an integer underflow, resulting in an out-of-bounds read and application crash.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 96%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-09-23
Last modified	2026-10-01

Publisher (CNA): Foxit · Vendor: foxit

Last updated 2026-10-01 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-23 08:17 UTCPublished CVE record published
2026-10-01 20:23 UTCUpdated Record last modified

foxit pdf editor UPGRADE

Affected: <= 13.2.5.63482 · >= 14.0.0.33046 and <= 14.0.7.33751 · >= 2023.1.0.15510 and <= 2023.3.0.23028 · >= 2024.1.0.23997 and <= 2024.4.1.27687 · >= 2025.1.0.27937 and <= 2025.3.0.35737 · >= 2026.1.0.36452 and <= 2026.2.0.39747

Fixed in: newer than 2026.2.0.39747

Safe to downgrade to: a release before 14.0.0.33046

1. Check installed version

apt-cache policy pdf-editor || rpm -q pdf-editor || pdf-editor --version

2. UPGRADE to newer than 2026.2.0.39747 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade pdf-editor

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pdf-editor

Note

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

3. If no update is available yet, DOWNGRADE to a release before 14.0.0.33046 (Debian / Ubuntu)

apt-cache madison pdf-editor sudo apt install pdf-editor=<VERSION_BEFORE_14.0.0.33046> sudo apt-mark hold pdf-editor

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list pdf-editor sudo dnf downgrade pdf-editor-<VERSION_BEFORE_14.0.0.33046> sudo dnf versionlock add pdf-editor

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

foxit pdf reader UPGRADE

Affected: <= 2026.2.0.39747

Fixed in: newer than 2026.2.0.39747

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 2026.2.0.39747 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pdf-reader

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-2026-91817?

pdf editor: upgrade to newer than 2026.2.0.39747; pdf reader: upgrade to newer than 2026.2.0.39747. Exact commands for each OS are on this page.

Is CVE-2026-91817 being exploited?

CVE-2026-91817 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-2026-91817 affect?

CVE-2026-91817 affects pdf editor, pdf reader. Severity is medium (CVSS 6.1). A heap-based out-of-bounds read vulnerability exists in Foxit PDF Editor/Reader’s handling of wide strings in embedded PDF JavaScript. Insufficient validation of string-deletion ranges can cause an integer underflow, resulting in an out-of-

How urgent is CVE-2026-91817?

Priority 22/100. No elevated risk signals yet.

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References

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