ContextForge MCP Gateway: Authentication Bypass by Capture-replay
CVE-2026-110278 is a high-severity authentication bypass by capture-replay vulnerability in ContextForge MCP Gateway from IBM, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected ContextForge MCP Gateway versions: 1.0.0 through 1.1.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.24% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of ContextForge MCP Gateway you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| IBM | ContextForge MCP Gateway | 1.0.0 through 1.1.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (us.ibm.com).
Official description
IBM ContextForge MCP Gateway 1.0.0 through 1.1.0 could allow an attacker to replay identity propagation claims signatures or expose sensitive user identity information to third-party MCP servers due to static signature payloads and missing per-gateway configuration checks during tool invocation.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass by Capture-replay
A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
How developers prevent this class of flaw
- Utilize some sequence or time stamping functionality along with a checksum which takes this into account in order to ensure that messages can be parsed only once.
- Since any attacker who can listen to traffic can see sequence numbers, it is necessary to sign messages with some kind of cryptography to ensure that sequence numbers are not simply doctored along with content.
More Authentication Bypass by Capture-replay vulnerabilities (CWE-294)
Timeline
- CVE record published.
References
Other references
Other vulnerabilities in ContextForge MCP Gateway
- 8.1 High severity
- 8.8 High severity
- 9.6 Critical severity
Recent Authentication Bypass by Capture-replay vulnerabilities
- 9.2 Critical severity
- 8.9 High severity
- 7.4 High severity
- 9.8 Critical severity
- 9.1 Critical severity
- 7.4 High severity
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