emacs: Improper Neutralization of Special Elements used in a Command
CVE-2023-2491 is a high-severity improper neutralization of special elements used in a command vulnerability in emacs, 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. There is no confirmed exploitation so far. EPSS estimates a 0.46% 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 emacs you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Emacs | emacs | Not specified in the record | Not stated |
| Red Hat | Enterprise Linux | 8.0; 9.0 | Not stated |
| Red Hat | Enterprise Linux EUS | 8.8; 9.2 | Not stated |
| Red Hat | Enterprise Linux Server AUS | 8.8; 9.2 | Not stated |
| Red Hat | Enterprise Linux Server TUS | 8.8 | 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
- 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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
A flaw was found in the Emacs text editor. Processing a specially crafted org-mode code with the "org-babel-execute:latex" function in ob-latex.el can result in arbitrary command execution. This CVE exists because of a CVE-2023-28617 security regression for the emacs package in Red Hat Enterprise Linux 8.8 and Red Hat Enterprise Linux 9.2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in a Command
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- If possible, ensure that all external commands called from the program are statically created.
- Run time: Run time policy enforcement may be used in an allowlist fashion to prevent use of any non-sanctioned commands.
More Improper Neutralization of Special Elements used in a Command vulnerabilities (CWE-77)
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
- access.redhat.com/errata/RHSA-2023:2626Third Party Advisory
- access.redhat.com/errata/RHSA-2023:3104Third Party Advisory
- access.redhat.com/security/cve/CVE-2023-2491Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2192873Issue Tracking, Third Party Advisory
Recent Improper Neutralization of Special Elements used in a Command vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 9.8 Critical severity
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