Openbsd: Incorrect Conversion between Numeric Types
CVE-2022-27882 is a high-severity incorrect conversion between numeric types vulnerability in Openbsd, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Openbsd versions: 6.9; 7.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.91% chance of exploitation within 30 days, higher than 80% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Openbsd you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on ftp.openbsd.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from NVD's product matching. 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
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 2.0 | 5.0 | Medium | NVD |
Official description
slaacd in OpenBSD 6.9 and 7.0 before 2022-03-22 has an integer signedness error and resultant heap-based buffer overflow triggerable by a crafted IPv6 router advertisement. NOTE: privilege separation and pledge can prevent exploitation.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Conversion between Numeric Types
When converting from one data type to another, such as long to integer, data can be omitted or translated in a way that produces unexpected values. If the resulting values are used in a sensitive context, then dangerous behaviors may occur.
How developers prevent this class of flaw
- Avoid making conversion between numeric types. Always check for the allowed ranges.
More Incorrect Conversion between Numeric Types vulnerabilities (CWE-681)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- security.netapp.com/advisory/ntap-20220506-0005/Third Party Advisory
Technical write-ups (may include proof of concept)
- blog.quarkslab.com/heap-overflow-in-openbsds-slaacd-via-router-advertisement.htmlExploit, Third Party Advisory
Other vulnerabilities in Openbsd
- 9.2 Critical severity
- 7.8 High severity
- 7.5 High severity
- 9.8 Critical severity
- 7.3 High severity
- 9.8 Critical severity
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