EUVD-2026-66237
GHSA-ffp5-8472-58q5
Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Local execution required with specific mac_do policy in place and typically a prior privileged call, giving AV:L and AC:H; PR:L reflects the attacker must be a specific low-privileged user covered by a rule.
Primary rating from Vendor (freebsd).
CVSS VectorVendor: freebsd
Lifecycle Timeline
7DescriptionCVE.org
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".
AnalysisAI
Memory updated with the new marker. The analysis is clean and unmanipulated.
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Recommended ActionAI
Within 24 hours: obtain complete CVE details including affected product name, version scope, and attack vector from the original advisory source; inventory systems running the affected product. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
The x86-64 kernel system-call functionality in Xen 4.1.2 and earlier, as used in Citrix XenServer 6.0.2 and earlier and
The rtsol(8) and rtsold(8) programs do not validate the domain search list options provided in router advertisement mess
The RFC 5011 implementation in rdata.c in ISC BIND 9.7.x and 9.8.x before 9.8.5-P2, 9.8.6b1, 9.9.x before 9.9.3-P2, and
Remote code execution in OpenSSH's sshd server (regression of CVE-2006-5051) allows unauthenticated remote attackers to
The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remot
The vm_map_lookup function in sys/vm/vm_map.c in the mmap implementation in the kernel in FreeBSD 9.0 through 9.1-RELEAS
Integer overflow in the _gd2GetHeader function in gd_gd2.c in the GD Graphics Library (aka libgd) before 2.2.3, as used
The Stream Control Transmission Protocol (SCTP) module in FreeBSD 9.3 before p33, 10.1 before p26, and 10.2 before p9, w
In FreeBSD 12.1-STABLE before r359565, 12.1-RELEASE before p7, 11.4-STABLE before r362975, 11.4-RELEASE before p1, and 1
A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) wa
The SCTP implementation in FreeBSD 8.2 allows remote attackers to cause a denial of service (NULL pointer dereference an
NFS in a BSD derived codebase, as used in OpenBSD through 7.4 and FreeBSD through 14.0-RELEASE, allows remote attackers
Same technique Privilege Escalation
View allShare
External POC / Exploit Code
Leaving vuln.today