traefik: Exposure of Data Element to Wrong Session
CVE-2026-114637 is a high-severity exposure of data element to wrong session vulnerability in traefik, with a CVSS 3.1 base score of 8.7 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 3.7.14 as the first without the flaw, so updating traefik to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.28% 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
- Update traefik to 3.7.14 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:C/C:H/I:H/A:N. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.0 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 8.7 | High | CNA (vulncheck.com) |
Official description
Traefik from v3.2.0 before v3.7.14 contains an authentication bypass vulnerability in the experimental FastProxy connection pool, which fails to pin NTLM/Negotiate-authenticated backend connections to their frontend connection. Unauthenticated clients can be handed a pooled keep-alive backend connection where a victim completed an NTLM or Negotiate handshake, letting them read victim data and act as that victim.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Exposure of Data Element to Wrong Session
The product does not sufficiently enforce boundaries between the states of different sessions, causing data to be provided to, or used by, the wrong session.
How developers prevent this class of flaw
- Protect the application's sessions from information leakage. Make sure that a session's data is not used or visible by other sessions.
- Use a static analysis tool to scan the code for information leakage vulnerabilities (e.g. Singleton Member Field).
- In a multithreading environment, storing user data in Servlet member fields introduces a data access race condition. Do not use member fields to store information in the Servlet.
More Exposure of Data Element to Wrong Session vulnerabilities (CWE-488)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
Other vulnerabilities in traefik
- 8.7 High severity
- 8.7 High severity
- 9.3 Critical severity
- 8.7 High severity
- 8.7 High severity
- 8.7 High severity
Recent Exposure of Data Element to Wrong Session vulnerabilities
- 8.1 High severity
- 8.1 High severity
- 9.1 Critical severity
- 7.3 High severity
- 7.5 High severity
- 9.8 Critical severity
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