CVE.org (no NVD analysis yet)· CNA apache

CVE-2026-88920: Apache WSS4J: SAML Sender-Vouches Authentication Bypass

Noroxi assessment

Priority: Monitor (action score 39/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.58% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: Apache Software Foundation Apache WSS4J 2.4.4, 3.0.6, 4.0.2.

Low priority for now. Upgrade to Apache Software Foundation Apache WSS4J 2.4.4, 3.0.6, 4.0.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

An authentication bypass in the DOM security processor in Apache WSS4J allows unauthenticated remote attackers to forge authenticated SOAP messages via a crafted unsigned SAML sender-vouches assertion containing an attacker-controlled key. Users are recommended to upgrade to versions 4.0.2 or 3.0.6 or 2.4.4, which fix this issue.

CriticalCVSS 9.8 · v3.1—No exploit Fix available

EUVD-2026-89793

Published: Sep 30, 2026
Updated: Oct 2, 2026
EPSS: 0.5% · 48th percentile
CWE: CWE-287

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 39 / 40 · 9.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.5%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
apache	wss4j	cpe:2.3:a:apache:wss4j

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

apache wss4jbefore 2.4.4
apache wss4j3.0.0 and later · before 3.0.6
apache wss4j4.0.0 and later · before 4.0.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

Apache Software Foundation Apache WSS4J
- 4.0.0 and later · before 4.0.2affected · semver
- 3.0.0 and later · before 3.0.6affected · semver
- before 2.4.4affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	wss4j	from 0	—

Same product

apache: all records

Other highest-scoring records for the same primary product.

CVE-2026-89238Apache WSS4J: WSS4J EncryptedHeader child confusion causing wrong protected-header selection
36Monitor
CVE-2026-87830Apache WSS4J: Streaming WS-SecurityPolicy validation may skip element-protection checks.
36Monitor
CVE-2015-0226Apache WSS4J before 1.6.17 and 2.0.x before 2.0.2 improperly leaks information about decryption failures when decrypting an encrypted key or
32Monitor

Published before and after this one in the same product

← EarlierCVE-2015-0227Feb 12, 2015 · Apache WSS4J before 1.6.17 and 2.x before 2.0.2 allows remote attackers to bypass the requireSignedEncryptedDataElements configuration via a
22Monitor
← EarlierCVE-2026-85532Sep 30, 2026 · Apache WSS4J: Insufficient Validation of Derived-Key Parameters
30Monitor
Later →CVE-2026-92121Sep 30, 2026 · Apache WSS4J: WS-SecurityPolicy signature checks skipped in the streaming code after an STR-Transform reference
30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Apache Software Foundation Apache WSS4J	2.4.4	Vendor (CNA)
Apache Software Foundation Apache WSS4J	3.0.6	Vendor (CNA)
Apache Software Foundation Apache WSS4J	4.0.2	Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedSep 30, 2026
Fix recordedSep 30, 2026same day
TodayNov 8, 2026+39 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

n0mi1kfinder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

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

nvd-secondary

Root cause

Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

The bug in code

The whole CWE-287 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1app.use("/admin", requireSession, adminRouter);
2

3// Route added later skips the middleware
4app.post("/admin-api/config", updateConfig);

Fixed

1const admin = express.Router();
2admin.use(requireSession, requireRole("admin"));
3

4admin.post("/config", updateConfig);
5app.use("/admin", admin);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Change log

CVSS— → 9.8Sep 30, 2026, 9:07 PM UTC
Severity— → criticalSep 30, 2026, 9:07 PM UTC
SSVC exploitation— → noneSep 30, 2026, 9:07 PM UTC
Exploit maturity— → noneSep 30, 2026, 1:07 PM UTC
Fix✗ → ✓Sep 30, 2026, 1:07 PM UTC

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References

lists.apache.org/thread.html/grt43m3bgbzz0mk0cnho3rcybb1j01z9

Show all references (1 more)

www.openwall.com/lists/oss-security/2026/09/30/10

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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