CVE-2026-4374: Improper Restriction of XML External Entity Reference vulnerability in RTI Connext Professional (Recording Ser

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-4374 is a critical-severity flaw (CVSS 9.1) affecting connext professional. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper Restriction of XML External Entity Reference vulnerability in RTI Connext Professional (Recording Service,Routing Service,Queueing Service,Cloud Discovery Service,Observability Collector) allows Serialized Data External Linking, Data Serialization External Entities Blowup. This issue affects Connext Professional: from 7.4.0 before 7.7.0, from 7.0.0 before 7.3.1.1, from 6.1.0 before 6.1.2.34, from 6.0.0 before 6.0.*, from 5.3.0 before 5.3

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 86%)
CISA exploited list	No
Weakness	CWE-611
Published	2026-04-01
Last modified	2026-09-22

Publisher (CNA): RTI · Vendor: rti

Last updated 2026-09-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-01 02:16 UTCPublished CVE record published
2026-09-22 18:17 UTCUpdated Record last modified

rti connext professional UPGRADE

Affected: >= 5.3.0 and <= 5.3.1.45 · >= 6.0.0 and <= 6.0.1.40 · >= 6.1.0 and <= 6.1.2.27 · >= 7.0.0 and < 7.3.1.1 · >= 7.4.0 and < 7.7.0

Fixed in: 7.3.1.1, 7.7.0

Safe to downgrade to: a release before 5.3.0

1. Check installed version

apt-cache policy connext-professional || rpm -q connext-professional || connext-professional --version

2. UPGRADE to 7.3.1.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade connext-professional

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade connext-professional

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 5.3.0 (Debian / Ubuntu)

apt-cache madison connext-professional sudo apt install connext-professional=<VERSION_BEFORE_5.3.0> sudo apt-mark hold connext-professional

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

dnf --showduplicates list connext-professional sudo dnf downgrade connext-professional-<VERSION_BEFORE_5.3.0> sudo dnf versionlock add connext-professional

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-2026-4374?

connext professional: upgrade to 7.3.1.1, 7.7.0. Exact commands for each OS are on this page.

Is CVE-2026-4374 being exploited?

CVE-2026-4374 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-2026-4374 affect?

CVE-2026-4374 affects connext professional. Severity is critical (CVSS 9.1). Improper Restriction of XML External Entity Reference vulnerability in RTI Connext Professional (Recording Service,Routing Service,Queueing Service,Cloud Discovery Service,Observability Collector) allows Serialized Data External Linking, Da

How urgent is CVE-2026-4374?

Priority 40/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-30799 HIGH 8.1 UPGRADE Missing Authentication for Critical Function vulnerability in RTI Connext Professional (Security Plugins) allo
CVE-2026-2467 HIGH 8.1 UPGRADE Heap-based Buffer Overflow vulnerability in RTI Connext Professional (Core Libraries) allows Overflow Variable
CVE-2026-2674 HIGH 8.1 UPGRADE Out-of-bounds Write vulnerability in RTI Connext Professional (Queueing Service,Core Libraries,Persistence Ser
CVE-2026-2675 MEDIUM 6.5 UPGRADE Missing Authentication for Critical Function vulnerability in RTI Connext Professional (Security Plugins) allo
CVE-2026-7300 MEDIUM 6.5 UPGRADE Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in RTI Connext Profession

References

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