CVE-2026-11541: IBM WebSphere Application Server and Liberty HTTP Request Smuggling (CVE-2026-11541)

15

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)+5
Technical severity (critical)+10

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

0.42%

ahead of 34% of scored CVEs · Oct 14, 2026

Affects

Ibm

CICS Transaction Gateway for Multiplatforms and 1 more

CVSS base

9.8

Critical · 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 (Ibm CICS Transaction Gateway for Multiplatforms, Ibm Websphere Application Server).
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 (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Ibm	CICS Transaction Gateway for Multiplatforms	version 9.1version 9.2version 9.3version 10.1	Vulnerable	CVE Program (cve.org) e CISA ADP
Ibm	Websphere Application Server	≥ 8.5.0.0 and < 8.5.5.31≥ 9.0.0.0 and < 9.0.5.29≥ 17.0.0.3 and ≤ 26.0.0.6	Vulnerable	NIST National Vulnerability Database

Attack characteristics

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

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

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
9.8	CVSS 3.1	Critical	3.9	5.9	nvd@nist.gov via NIST National Vulnerability Database
7.4	CVSS 3.1	High	2.2	5.2	psirt@us.ibm.com via NIST National Vulnerability Database
7.4	CVSS 3.1	High	—	—	ibm via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 9.8 (NVD (NIST)) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-444 · HTTP Request Smuggling

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.42%

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).
Look for parameters with command/query metacharacters and unexpected child processes of the service.

web/proxy/WAF logsnetwork IDS/IPSapplication logsendpoint telemetry (EDR)

Analysis and videos

CVE-2026-11541: IBM WebSphere Application Server and Liberty HTTP Request Smuggling
IBM published CVE-2026-11541 on 2026-06-30 for an HTTP request smuggling flaw (CWE-444) affecting IBM WebSphere Application Server and WebSphere Application Server Liberty. NVD rates it 9.8 Critical under CVSS 3.1, while IBM's own CVSS 3.1 score in the record is 7.4. The record does not list fixed versions, and no confirmed exploitation appears in the sources consulted.

Timeline

What happened to this CVE, newest first.

2026
Affected products added · ibm/cics transaction gateway for multiplatforms
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 9.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jun 30, 2026 · ibm

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

www.ibm.com/support/pages/node/7281750
vendor-advisory, patch, NIST National Vulnerability Database

Elsewhere on this site

Ibm
every CVE for this vendor

Injection
same class

CWE-444
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-105442 IBM WebSphere Application Server and WebSphere Application Server Liberty are affected by a deserialization of untrusted data 2d
High CVE-2026-101294 IBM WebSphere Application Server and WebSphere Application Server Liberty are affected by a missing cryptographic step 2d
High CVE-2026-95680 IBM WebSphere Application Server is affected by an authorization bypass 2d
High CVE-2026-93907 IBM WebSphere Application Server 8.5, and 9.0 could allow a remote attacker to bypass... 2d
High CVE-2026-103499 IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.10 and IBM WebSphere... 2d
Critical CVE-2026-14525 Missing Authentication for Critical Function in Ibm Websphere Application Server Aug 13, 2026

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-2026-11541 is "IBM WebSphere Application Server and Liberty HTTP Request Smuggling (CVE-2026-11541)", rated Critical. It affects CICS Transaction Gateway for Multiplatforms (Ibm); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. EPSS 0.42% 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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