logchimp: Authorization Bypass Through User-Controlled Key
CVE-2026-121560 is a high-severity authorization bypass through user-controlled key vulnerability in logchimp, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 0.9.3 as the first without the flaw, so updating logchimp to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.45% 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 logchimp to 0.9.3 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Logchimp | logchimp | 0.9.0-alpha.1 up to, but not including, 0.9.3 | 0.9.3 |
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
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.1 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 7.1 | High | CNA (vulncheck.com) |
Official description
LogChimp 0.9.0-alpha.1 before 0.9.3 contains an authorization bypass vulnerability that allows authenticated post authors to modify any other post by supplying mismatched postId and id body parameters. Attackers can set postId to their own post and id to an enumerated victim post UUID to overwrite its title, slug, content, boardId and roadmap_id.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authorization Bypass Through User-Controlled Key
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
How developers prevent this class of flaw
- For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
- Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
- Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.
More Authorization Bypass Through User-Controlled Key vulnerabilities (CWE-639)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
- github.com/logchimp/logchimp
- github.com/logchimp/logchimp/blob/v0.9.2/packages/server/src/controllers/post/updatePost.ts#L67
- github.com/logchimp/logchimp/blob/v0.9.2/packages/server/src/middlewares/postExists.ts#L72-L77
- vulncheck.com/advisories/logchimp-before-0.9.3-authorization-bypass-via-patch-api-v1-posts
Recent Authorization Bypass Through User-Controlled Key vulnerabilities
- 8.3 High severity
- 7.6 High severity
- 8.8 High severity
- 8.4 High severity
- 8.4 High severity
- 8.8 High severity
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