# CVE-2026-58092: Unauthorized credential switching > A kernel bug in FreeBSD allows unauthorized credential switching to set the primary group ID to 0, potentially enabling privilege escalation under specific MAC configurations. - **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** No - **Published:** 26 Aug 2026 - **Updated:** 27 Aug 2026 - **Also known as:** GHSA-ffp5-8472-58q5 ## What is CVE-2026-58092? CVE-2026-58092 is a high-severity vulnerability in Freebsd Freebsd, published on 26 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim. ### Official description In FreeBSD 15.0, the kernel structure used to represent user credentials changed: previously the primary group ID was stored in the first element of the array containing the list of supplementary group IDs, whereas now the primary group ID is stored in a dedicated field. This change was largely internal to the kernel and not user-visible. One function, group_is_primary(), was not properly updated as a part of this transition. This function is used by mac_do to determine the primary group ID of the credential after applying a transition rule, used when the rule target does not explicitly specify a group. As a result, with certain mac_do rules, it is possible for a credential switch to incorrectly set the primary group ID to the ID stored in the first element of the original credential's supplementary group array. If the list of supplementary groups is empty, this value will be 0, corresponding to the "wheel" group. For example, a rule such as "uid=1001>uid=1002" can be abused to set the primary group ID to 0 even if the process did not originally belong to group 0. Certain mac_do rules can be abused to set a process' group ID to 0. Note however, that the rule must apply to the caller in order for the bug to be triggered, e.g., given the ruleset "uid=1001>uid=1002", the user must have user ID 1001 in order to trigger the bug. Further, logged-in users will in general have a non-empty supplementary group list, in which case the bug can at worst be used to set the credential's first supplementary group ID as its primary group ID. Processes must explicitly remove themselves from all supplementary groups, using the privileged setgroups(2) system call, in order to exploit the bug to set 0 as the primary group ID. Since membership in group 0 is often used to enable controlled privilege escalation, the bug might be further exploitable to obtain root privileges, depending on the system configuration. For instance, a ruleset such as the following could be exploited by a process running as user 1001 and with an empty supplementary group list: "uid=1001>uid=1002;gid=0>uid=0". Weakness: CWE-288 (Authentication Bypass Using an Alternate Path or Channel) ## Which versions are affected by CVE-2026-58092? It affects 1 product. Products: Freebsd Freebsd. ## How do I fix CVE-2026-58092? No fix has been published for CVE-2026-58092 yet. Limit exposure of the affected software until one is available. ## Is CVE-2026-58092 being exploited? There is no known exploitation of CVE-2026-58092 in the wild and no public exploit code. ## Other vulnerabilities in Freebsd Freebsd - [CVE-2018-17160](https://insights.sbomify.com/CVE-2018-17160/): Memory corruption in FreeBSD (critical 10.0) - [CVE-2014-3954](https://insights.sbomify.com/CVE-2014-3954/): Memory corruption in n/a (critical 10.0) - [CVE-2006-4304](https://insights.sbomify.com/CVE-2006-4304/): Memory corruption in n/a (critical 10.0) - [CVE-2006-0226](https://insights.sbomify.com/CVE-2006-0226/): Integer overflow in n/a (critical 10.0) - [CVE-2004-0002](https://insights.sbomify.com/CVE-2004-0002/): Denial of service in n/a (critical 10.0) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-58092 and fix it if it is affected. What it is: CVE-2026-58092 is a high-severity vulnerability in Freebsd Freebsd, published on 26 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-58092 in the wild and no public exploit code. Affected product: Freebsd Freebsd. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-58092/ (Markdown: https://insights.sbomify.com/CVE-2026-58092/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58092 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58092 - OSV: https://osv.dev/vulnerability/CVE-2026-58092 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-58092/ Summaries are generated and may contain mistakes; the official description above is the record.