CVE-2026-50623: An authentication bypass vulnerability exists in the OAuth2 TokenIntrospectionService in Apache CXF. Due to a

Routine

MEDIUM 4.8REMOTEWATCHLISTUPGRADE

CVE-2026-50623 is a medium-severity flaw (CVSS 4.8) affecting cxf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An authentication bypass vulnerability exists in the OAuth2 TokenIntrospectionService in Apache CXF. Due to a missing 'throw' keyword in the security context check, the introspection endpoint (/services/oauth2/introspect) can be accessed by any unauthenticated network attacker. However note that this is a safeguard only in the case that someone forgot to enable authentication on the service. Users are recommended to upgrade to version 4.2.2 or 4.

Why this priority

Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-287
Published	2026-06-12
Last modified	2026-10-25

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-12 10:16 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

apache cxf UPGRADE

Affected: < 4.1.7 · >= 4.2.0 and < 4.2.2

Fixed in: 4.1.7, 4.2.2

Safe to downgrade to: a release before 4.2.0

1. Check installed version

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

2. UPGRADE to 4.1.7 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cxf

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 4.2.0 (Debian / Ubuntu)

apt-cache madison cxf sudo apt install cxf=<VERSION_BEFORE_4.2.0> sudo apt-mark hold cxf

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

dnf --showduplicates list cxf sudo dnf downgrade cxf-<VERSION_BEFORE_4.2.0> sudo dnf versionlock add cxf

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-2026-50623?

cxf: upgrade to 4.1.7, 4.2.2. Exact commands for each OS are on this page.

Is CVE-2026-50623 being exploited?

CVE-2026-50623 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-2026-50623 affect?

CVE-2026-50623 affects cxf. Severity is medium (CVSS 4.8). An authentication bypass vulnerability exists in the OAuth2 TokenIntrospectionService in Apache CXF. Due to a missing 'throw' keyword in the security context check, the introspection endpoint (/services/oauth2/introspect) can be accessed by

How urgent is CVE-2026-50623?

Priority 34/100. Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

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CVE-2026-68079 CRITICAL 9.8 UPGRADE In Apache CXF's DefaultEncryptingCodeDataProvider, a captured authorization code can be redeemed an unlimited
CVE-2026-61466 CRITICAL 9.1 UPGRADE In Apache CXF's OAuth2 Dynamic Client Registration endpoint, the authorization server accepts and stores the `
CVE-2026-57817 HIGH 8.1 UPGRADE The OpenID Connect Core 1.0 specification mandates that the RP MUST validate the `c_hash` parameter when opera
CVE-2026-54225 HIGH 7.5 UPGRADE Apache CXF allows to control the maximum attachment size via the "attachment-max-size"

References

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