LibreOffice: Improper Validation of Array Index
CVE-2023-0950 is a high-severity improper validation of array index vulnerability in LibreOffice from The Document Foundation, 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 unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 7.4.6, 7.5.1 as the first without the flaw, so updating LibreOffice to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.3% 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 LibreOffice to 7.4.6 or 7.5.1, whichever matches your release line, or a later version.
- Read the advisory on libreoffice.org for workarounds and exact fixed builds.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| The Document Foundation | LibreOffice | 7.4 up to, but not including, 7.4.6; 7.5 up to, but not including, 7.5.1 | 7.4.6, 7.5.1 |
| Debian | Debian Linux | 10.0 | 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
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- 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:N/UI:R/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
Improper Validation of Array Index vulnerability in the spreadsheet component of The Document Foundation LibreOffice allows an attacker to craft a spreadsheet document that will cause an array index underflow when loaded. In the affected versions of LibreOffice certain malformed spreadsheet formulas, such as AGGREGATE, could be created with less parameters passed to the formula interpreter than it expected, leading to an array index underflow, in which case there is a risk that arbitrary code could be executed. This issue affects: The Document Foundation LibreOffice 7.4 versions prior to 7.4.6; 7.5 versions prior to 7.5.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Validation of Array Index
The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.
How developers prevent this class of flaw
- Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, Ada allows the programmer to constrain the values of a variable and languages such as Java and Ruby will allow the programmer to handle exceptions when an out-of-bounds index is accessed.
- Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND.
More Improper Validation of Array Index vulnerabilities (CWE-129)
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
- debian.org/security/2023/dsa-5415Third Party Advisory
Other references
Other vulnerabilities in LibreOffice
- 8.5 High severity
- 7.8 High severity
- 7.3 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Recent Improper Validation of Array Index vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 8.8 High severity
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
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