Medium SSRF

CVE-2026-8355 — IBM ContextForge MCP Gateway is affected by server-side request forgery

IBM ContextForge MCP Gateway 0.1.0 through 1.0.5 is vulnerable to a server-side request Forgery (SSRF) that allows authenticated users with gateway creation privileges to perform arbitrary HTTP POST requests to internal network resources and cloud metadata endpoints. The vulnerability occurs during OAuth-enabled gateway registration when the system fails to validate the oauth_config.token_url parameter. When registering a gateway with OAuth client credentials authentication, an attacker can supply a malicious token_url pointing to internal services, cloud metadata endpoints (AWS IMDSv1, GCP, Azure), or localhost-bound services. The application immediately performs an HTTP POST request to the attacker-controlled URL with form-encoded credentials in the body. If the response cannot be parsed as a valid OAuth token response, up to 256 characters of the response body are reflected back to the attacker in the HTTP 502 error message. This vulnerability bypasses existing SSRF protections that are applied to the gateway.url field but not to OAuth configuration parameters.

Published Oct 19, 2026 · Updated Oct 20, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: ibm

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 0.2% (30-day exploitation probability)+1
Technical severity (medium)+3

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

0.18%

ahead of 7% of scored CVEs · Oct 23, 2026

Affects

Ibm

ContextForge MCP Gateway

CVSS base

5.4

Medium · 2 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

can an attacker script the kill-chain steps

Technical impact

Partial

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 ContextForge MCP Gateway).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (ssrf), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Ibm	ContextForge MCP Gateway	≥ 0.1.0 and ≤ 1.0.5	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

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

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
5.4	CVSS 3.1	Medium	2.8	2.5	134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
5.4	CVSS 3.1	Medium	—	—	CISA-ADP via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-918 · Server-Side Request Forgery (SSRF)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 20, 2026 → Oct 23, 2026 · 4 reading(s) · max 0.18%

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).
Monitor outbound requests from the server to internal IPs and cloud metadata endpoints.

web/proxy/WAF logsnetwork IDS/IPSegress traffic

Timeline

What happened to this CVE, newest first.

2026
CVSS changed · 5.4
Oct 20, 2026 · NIST National Vulnerability Database
Source status changed · Received → Awaiting Analysis
Oct 20, 2026 · NIST National Vulnerability Database
SSVC assessment updated
Oct 20, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 19, 2026
Affected products added · ibm/contextforge mcp gateway
Oct 19, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 19, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 19, 2026 · NIST National Vulnerability Database
CVE published
Oct 19, 2026 · ibm

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 19, 2026 – Oct 19, 2026

References

1 on the record

www.ibm.com/support/pages/node/7285723
vendor-advisory, patch, NIST National Vulnerability Database

Elsewhere on this site

Ibm
every CVE for this vendor

SSRF
same class

CWE-918
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-77825 IBM ContextForge MCP Gateway is affected by path traversal Sep 24, 2026
Medium CVE-2026-11918 IBM ContextForge MCP Gateway is affected by security filter bypass via nested payload structures Sep 15, 2026
Critical CVE-2026-78573 IBM ContextForge MCP Gateway is affected by use of default credentials Sep 10, 2026
High CVE-2026-18486 IBM ContextForge MCP Gateway is affected by credential disclosure and privilege escalation via jq filter execution Sep 4, 2026
Critical CVE-2026-77822 IBM ContextForge MCP Gateway is affected by server-side request forgery (DNS rebinding) via the A2A agent invocation endpoint Sep 4, 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-2026-8355 is "IBM ContextForge MCP Gateway is affected by server-side request forgery", rated Medium. It affects ContextForge MCP Gateway (Ibm); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.4 describes technical severity. EPSS 0.18% 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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