CVE-2021-43691: tripexpress v1.1 is affected by a path manipulation vulnerability in file system/helpers/dompdf/load_font.php

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2021-43691 is a critical-severity flaw (CVSS 9.8) affecting tripexpress. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

tripexpress v1.1 is affected by a path manipulation vulnerability in file system/helpers/dompdf/load_font.php. The variable src is coming from $_SERVER["argv"] then there is a path manipulation vulnerability.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.6% (top 25%)
CISA exploited list	No
Weakness	CWE-22
Published	2021-11-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: tripexpress project

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

Am I affected?

Timeline

2021-11-29 16:15 UTCPublished CVE record published
2026-06-17 04:11 UTCUpdated Record last modified

tripexpress project tripexpress DOWNGRADE

Affected: 1.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.1 (Debian / Ubuntu)

apt-cache madison tripexpress sudo apt install tripexpress=<VERSION_BEFORE_1.1> sudo apt-mark hold tripexpress

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list tripexpress sudo dnf downgrade tripexpress-<VERSION_BEFORE_1.1> sudo dnf versionlock add tripexpress

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.

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-2021-43691?

tripexpress: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-43691 being exploited?

CVE-2021-43691 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-2021-43691 affect?

CVE-2021-43691 affects tripexpress. Severity is critical (CVSS 9.8). tripexpress v1.1 is affected by a path manipulation vulnerability in file system/helpers/dompdf/load_font.php. The variable src is coming from $_SERVER["argv"] then there is a path manipulation vulnerability.

How urgent is CVE-2021-43691?

Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

References

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