CVE-2026-15554: Undertow-core: undertow: authentication bypass via ajp ssl_cert/is_ssl forgery

10

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.4% (30-day exploitation probability)+4
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

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

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.35%

ahead of 27% of scored CVEs · Oct 15, 2026

Affects

Red Hat

Red Hat JBoss Enterprise Application Platform 7 and 7 more

CVSS base

7.4

High · 3 source(s)

CISA SSVC assessment CISA

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

Exploitation

None

none · proof-of-concept · active

Automatable

No

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Red Hat Red Hat JBoss Enterprise Application Platform 7, Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7, Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 8…).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (cryptography), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Red Hat	Red Hat JBoss Enterprise Application Platform 7	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 8	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 9	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat JBoss Enterprise Application Platform 7.4.25	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 10	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

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

Attack vector

Network

Attack complexity

High

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Every base score collected

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

Score	Version	Severity	Expl.	Impact	Scored by
7.4	CVSS 3.1	High	2.2	5.2	secalert@redhat.com via NIST National Vulnerability Database
7.4	CVSS 3.1	High	—	—	GitHub, Inc. via GitHub Security Advisories
7.4	CVSS 3.1	High	—	—	redhat via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N (score shown at the top: secalert@redhat.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-295 · Improper Certificate Validation

Other CVEs with this weakness →

Detection

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

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Check TLS negotiations and unexpected certificates in the component’s traffic.

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · red hat/red hat jboss enterprise application platform 7.4.25, red hat/red hat jboss enterprise application platform 7.4
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 7.4
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Awaiting Analysis
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · Alertas do Telegram
CVE published
Aug 11, 2026 · redhat

Source activity

Repeated readings are counted rather than listed.

2× References added · Oct 15, 2026 – Oct 15, 2026
1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

12 on the record

access.redhat.com/errata/RHSA-2026:70230
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
github.com/advisories/GHSA-f478-cwfc-jqh3
GitHub Security Advisories
access.redhat.com/security/cve/CVE-2026-15554
vdb-entry, x_refsource_REDHAT, NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2026:70277
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2026:53646
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2026:53644
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
bugzilla.redhat.com/show_bug.cgi
issue-tracking, x_refsource_REDHAT, NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2026:53806
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2026:70228
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
access.redhat.com/errata/RHSA-2026:53645
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2026-15554
GitHub Security Advisories
access.redhat.com/errata/RHSA-2026:70229
vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database

Elsewhere on this site

Red Hat
every CVE for this vendor

Cryptography
same class

CWE-295
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-85634 Wildfly-core: wildfly-core: deployer rbac role privilege escalation via path traversal in deployment name 2h
High CVE-2026-93569 Io.netty/netty-codec-http2: http/1 absolute-form host mismatch is translated to http/2 :authority, overriding the request-target authority 27d
High CVE-2026-93568 Io.netty/netty-codec-http2: io.netty/netty-codec-http3: netty: http/2 and http/3 extended connect requests are downgraded as regular connect requests 27d
High CVE-2026-93567 Io.netty/netty-codec-http2: http/1 authority-form connect is translated to malformed http/2 connect with host-controlled :authority 27d
High CVE-2026-93564 Io.netty/netty-codec-haproxy: netty: haproxy proxy-v2 nested-tlv grandchild bytebuf reference-count leak (incomplete fix of pr #16881) 27d
Medium CVE-2026-10832 Org.wildfly.security/wildfly-elytron-asn1: unbounded memory allocation in wildfly elytron asn.1 derdecoder via crafted der payload 27d

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 fixed version, patch or mitigation documented.
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 record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-15554 is "Undertow-core: undertow: authentication bypass via ajp ssl_cert/is_ssl forgery", rated High. It affects Red Hat JBoss Enterprise Application Platform 7 (Red Hat); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.4 describes technical severity. EPSS 0.35% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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