Emacs: Incomplete List of Disallowed Inputs
CVE-2026-108976 is a high-severity incomplete list of disallowed inputs vulnerability in Emacs from GNU, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 31.2 as the first without the flaw, so updating Emacs to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.65% chance of exploitation within 30 days, higher than 52% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Emacs to 31.2 or a later version.
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
- LocalThe attacker needs local access or must trick a user into running something.
- 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
- 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (mitre.org).
Official description
GNU Emacs before 31.2 (and TRAMP through 2.8.2) allows OS command injection via a filename because tramp-user-regexp has an incomplete list of disallowed inputs. NOTE: this issue exists because of an incomplete fix for CVE-2026-79992.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incomplete List of Disallowed Inputs
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.
How developers prevent this class of flaw
- Do not rely exclusively on detecting disallowed inputs. There are too many variants to encode a character, especially when different environments are used, so there is a high likelihood of missing some variants. Only use detection of disallowed inputs as a mechanism for detecting suspicious activity. Ensure that you are using other protection mechanisms that only identify good input - such as lists of allowed inputs - and ensure that you are properly encoding your outputs.
More Incomplete List of Disallowed Inputs vulnerabilities (CWE-184)
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
Other references
Other vulnerabilities in Emacs
- 7.5 High severity
- 7.1 High severity
- 7.1 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
Recent Incomplete List of Disallowed Inputs vulnerabilities
- 7.8 High severity
- 9.2 Critical severity
- 7.8 High severity
- 7.5 High severity
- 8.8 High severity
- 7.1 High severity
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