What is CVE-2026-5430?

CVE-2026-5430 is Authentication Bypass via JWT Algorithm Mismatch in Multiple WSO2 Products Allows Account Takeover. The supplied enrichment data classifies it as Auth Bypass mapped to CWE-347 CWE-347.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

16 public PoC repositories reported; 1 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS, identity provider logs, authentication audit logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-5430 using CVSS 10, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

Workarounds are not confirmed from current sources. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVcriticalAuth Bypasspublic exploit

CVE-2026-5430

CVE-2026-5430 — Authentication Bypass via JWT Algorithm Mismatch in Multiple WSO2 Products Allows Account Takeover

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2026-5430 in CISA KEV with required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

The JWT authentication mechanism accepts tokens signed with algorithms other than those explicitly configured or supported. This allows an attacker to craft a JWT with an unsupported algorithm, which is then incorrectly validated, leading to unauthorized access. Successful exploitation of this vulnerability may result in unauthorized access to the system, including the potential compromise of administrative accounts and full account takeover. The CVSS score is adjusted to 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) in single-tenant deployments, reflecting that the impact is contained within a single security authority boundary.

Published Aug 6, 2026Updated Sep 24, 2026Sources: NVD, WSO2 (CNA), CISA, FIRST EPSS, GitHub, GitHub Security Advisory

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Sep 24, 2026

EPSS

ahead of 29% of scored CVEs

Affects

WSO2

20 products listed

CVSS base

critical

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Follow the instructions given on https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5328/#solution https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5328/#solution

CISA required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Federal deadline Sep 27, 2026 — in 2 days

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
WSO2	WSO2 Universal Gateway	4.5.0 to < 4.5.0.57	Vulnerable
WSO2	WSO2 Universal Gateway	4.6.0 to < 4.6.0.21	Vulnerable
WSO2	WSO2 Traffic Manager	4.5.0 to < 4.5.0.56	Vulnerable
WSO2	WSO2 Traffic Manager	4.6.0 to < 4.6.0.21	Vulnerable
WSO2	WSO2 API Control Plane	4.5.0 to < 4.5.0.58	Vulnerable
WSO2	WSO2 API Control Plane	4.6.0 to < 4.6.0.22	Vulnerable
WSO2	WSO2 API Manager	0 to < 4.1.0	Vulnerable
WSO2	WSO2 API Manager	4.1.0 to < 4.1.0.257	Vulnerable
WSO2	WSO2 API Manager	4.2.0 to < 4.2.0.197	Vulnerable
WSO2	WSO2 API Manager	4.3.0 to < 4.3.0.108	Vulnerable
WSO2	WSO2 API Manager	4.4.0 to < 4.4.0.72	Vulnerable
WSO2	WSO2 API Manager	4.5.0 to < 4.5.0.57	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Changed

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
10	CVSS 3.1	critical	3.9	6	CNA, WSO2 (CNA), GHSA

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

Weakness & attack patterns

CWE-347

Inferred from the weakness class — not observed against this CVE.

CAPEC-115 · Authentication BypassCAPEC-94 · Adversary in the Middle

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Sep 24, 2026

Federal deadline

Sep 27, 2026

in 2 days

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

1 of the 5 sampled are weaponized

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Prioritize edge telemetry for network-reachable WSO2 Universal Gateway, WSO2 Traffic Manager, WSO2 API Control Plane, WSO2 API Manager, WSO2 Carbon API Manager Rest API Utility.
Monitor for scanner or exploit-pattern traffic after 16 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPSidentity provider logsauthentication audit logs

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added to CISA KEV catalog
Sep 24, 2026 · CISA
Added · CVSS 3.1 10.0 (AV:N)
Sep 24, 2026 · NVD
Initial · CVE published
Aug 6, 2026 · NVD
Added · GHSA-j7vh-5w8q-4m4x published (critical)
Aug 6, 2026 · GitHub Security Advisory

References

6 on the record

security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5328/
Vendor Advisory
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-5430
US Government Resource
nvd.nist.gov/vuln/detail/CVE-2026-5430
NVD, Vendor Advisory
github.com/advisories/GHSA-j7vh-5w8q-4m4x
Exploit, Third Party Advisory
www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
US Government Resource
www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
US Government Resource

Coverage

2 stories from the feeds we poll

Elsewhere on this site

WSO2every CVE for this vendor
September 2026what else CISA listed
Auth Bypasssame class
CWE-347other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-5430 is Authentication Bypass via JWT Algorithm Mismatch in Multiple WSO2 Products Allows Account Takeover, a critical vulnerability affecting WSO2 Universal Gateway, WSO2 Traffic Manager, WSO2 API Control Plane, WSO2 API Manager, WSO2 Carbon API Manager Rest API Utility from WSO2. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 16 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 10 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.