CVE-2026-40343: free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) m

Q: How do I fix CVE-2026-40343?

free5gc: upgrade to newer than 4.2.1; udr: upgrade to newer than 1.4.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-40343 being exploited?

CVE-2026-40343 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-2026-40343 affect?

CVE-2026-40343 affects free5gc, udr. Severity is medium (CVSS 5.8). free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.2, a fail-open request handling flaw in the UDR service causes the `/nudr

Q: How urgent is CVE-2026-40343?

Priority 49/100. EPSS top 5%: very likely to be exploited; Remotely exploitable, no login, no user action

This week

MEDIUM 5.8REMOTEUPGRADEUPGRADE

CVE-2026-40343 is a medium-severity flaw (CVSS 5.8) affecting free5gc, udr. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.2, a fail-open request handling flaw in the UDR service causes the `/nudr-dr/v2/policy-data/subs-to-notify` POST handler to continue processing requests even after request body retrieval or deserialization errors. This may allow unintended creation of Policy Data notification subscr

Why this priority

EPSS top 5%: very likely to be exploited
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.8 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	8.6% (top 5%)
CISA exploited list	No
Weakness	CWE-754
Published	2026-04-22
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: free5gc

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-22 00:16 UTCPublished CVE record published
2026-10-26 22:10 UTCUpdated Record last modified

free5gc free5gc UPGRADE

Affected: <= 4.2.1

Fixed in: newer than 4.2.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy free5gc || rpm -q free5gc || free5gc --version

2. UPGRADE to newer than 4.2.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade free5gc

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade free5gc

Note

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

free5gc udr UPGRADE

Affected: <= 1.4.2

Fixed in: newer than 1.4.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.4.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade udr

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-2026-40343?

free5gc: upgrade to newer than 4.2.1; udr: upgrade to newer than 1.4.2. Exact commands for each OS are on this page.

Is CVE-2026-40343 being exploited?

CVE-2026-40343 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-2026-40343 affect?

CVE-2026-40343 affects free5gc, udr. Severity is medium (CVSS 5.8). free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.2, a fail-open request handling flaw in the UDR service causes the `/nudr

How urgent is CVE-2026-40343?

Priority 49/100. EPSS top 5%: very likely to be exploited; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-41135 HIGH 7.5 UPGRADE UPGRADE free5GC UDR is the Policy Control Function (PCF) for free5GC, an an open-source project for 5th generation (5G
CVE-2026-41136 MEDIUM 5.3 UPGRADE UPGRADE free5GC AMF provides Access & Mobility Management Function (AMF) for free5GC, an an open-source project for 5t

References

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