VulnerabilityPublished 6 Aug 2026

CVE-2026-63687: Apache CXF · Insufficient Verification of Data Authenticity

Affects Apache CXFSource CVE Database V5

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Not known to be exploited · CVSS 9.1 Critical · fixed in 4.2.3 : patch Apache CXF as a priority.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 3.1 base score

9.1Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.2.3, 4.1.8, 3.6.12

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-7hjx-472h-3f7q

What to do

Upgrade Apache to 4.2.3, 4.1.8 or 3.6.12.

Affected software

Product	Affected	Fixed in
Apache Software FoundationApache CXF	Affected >=4.2.0 <4.2.3	Fixed in 4.2.3
Apache Software FoundationApache CXF	Affected >=4.0.0 <4.1.8	Fixed in 4.1.8
Apache Software FoundationApache CXF	Affected <3.6.12	Fixed in 3.6.12
MavenApache Software Foundation/org.apache.cxf:cxf-rt-rs-security-oauth2`pkg:maven/Apache Software Foundation/org.apache.cxf:cxf-rt-rs-security-oauth2`Other threats	Affected >=4.2.0 <4.2.3 >=4.0.0 <4.1.8 <3.6.12	Fixed in 4.2.3 4.1.8 3.6.12

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Users should upgrade Apache CXF to versions 4.2.3, 4.1.8, or 3.6.12, which contain fixes for this vulnerability. No other mitigation or temporary workaround is indicated. Patch status is confirmed by the vendor advisory recommending these versions.

Description

Apache CXF contains a vulnerability in its JwtRequestCodeFilter where security-sensitive parameters from a signed JWT are copied into the authorization parameter map without proper exclusion. This allows an attacker who can produce a validly-signed JWT (for example, if the client_secret is compromised) to substitute critical parameters such as code_challenge, code_challenge_method, nonce, and state, undermining PKCE integrity and OpenID Connect replay protection. Fixed versions 4.2.3, 4.1.8, and 3.6.12 address this issue.

Impact

Successful exploitation allows an attacker who can generate a validly-signed JWT to substitute critical security parameters, thereby undermining PKCE integrity and OpenID Connect replay protection. This can lead to replay attacks and potentially unauthorized access. The CVSS score of 9.1 (critical) reflects high confidentiality and integrity impact with no required privileges or user interaction.

CWE-345Insufficient Verification of Data Authenticity (opens in a new tab)
Class weaknessOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
JSON Hijacking (aka JavaScript Hijacking) (opens in a new tab)
Cache Poisoning (opens in a new tab)
DNS Cache Poisoning (opens in a new tab)
Spoofing of UDDI/ebXML Messages (opens in a new tab)
Application API Message Manipulation via Man-in-the-Middle (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Aug 2026, 16:58 UTC

WeaknessesCWE-345

Technical details

References

Community reviews

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