ConvertX: Inclusion of Functionality from Untrusted Control Sphere
CVE-2026-105080 is a critical-severity inclusion of functionality from untrusted control sphere vulnerability in ConvertX from C4illin, with a CVSS 3.1 base score of 9.9 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 0.19.0 as the first without the flaw, so updating ConvertX to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.41% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update ConvertX to 0.19.0 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
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
- 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
- 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
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (mitre.org).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.4 | Critical | CNA (mitre.org) |
| CVSS 3.1 | 9.9 | Critical | CNA (mitre.org) |
Official description
In ConvertX before 0.19.0, converters/calibre.ts does not block recipe files, and instead passes them to the ebook-convert program from Calibre. This affects executable code in a .recipe or .downloaded_recipe file.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Inclusion of Functionality from Untrusted Control Sphere
The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to inbox.txt and ID 2 could map to profile.txt. Features such as the ESAPI AccessReferenceMap provide this capability.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Inclusion of Functionality from Untrusted Control Sphere vulnerabilities (CWE-829)
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
Patches and release notes
Other vulnerabilities in ConvertX
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.8 High severity
Recent Inclusion of Functionality from Untrusted Control Sphere vulnerabilities
- 8.6 High severity
- 7.1 High severity
- 8.2 High severity
- 8.8 High severity
- 7.5 High severity
- 8.8 High severity
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