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CVE-2026-3038

Local DoS and possible privilege escalation via routing sockets

7.5 High

The rtsock_msg_buffer() function serializes routing information into a buffer. As a part of this, it copies sockaddr structures into a sockaddr_storage structure on the stack. It assumes that the source sockaddr length field had already been validated, but this is not necessarily the case, and it's possible for a malicious userspace program to craft a request which triggers a 127-byte overflow.

In practice, this overflow immediately overwrites the canary for the rtsock_msg_buffer() stack frame, resulting in a panic once the function returns.

The bug allows an unprivileged user to crash the kernel by triggering a stack buffer overflow in rtsock_msg_buffer(). In particular, the overflow will corrupt a stack canary value that is verified when the function returns; this mitigates the impact of the stack overflow by triggering a kernel panic.

Other kernel bugs may exist which allow userspace to find the canary value and thus defeat the mitigation, at which point local privilege escalation may be possible.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.65%Up 0.6 points since Mar 10, 2026
90%50%10%1%

What each source reports

CVE List Score used 7.5

Local DoS and possible privilege escalation via routing sockets

The rtsock_msg_buffer() function serializes routing information into a buffer. As a part of this, it copies sockaddr structures into a sockaddr_storage structure on the stack. It assumes that the source sockaddr length field had already been validated, but this is not necessarily the case, and it's possible for a malicious userspace program to craft a request which triggers a 127-byte overflow.

In practice, this overflow immediately overwrites the canary for the rtsock_msg_buffer() stack frame, resulting in a panic once the function returns.

The bug allows an unprivileged user to crash the kernel by triggering a stack buffer overflow in rtsock_msg_buffer(). In particular, the overflow will corrupt a stack canary value that is verified when the function returns; this mitigates the impact of the stack overflow by triggering a kernel panic.

Other kernel bugs may exist which allow userspace to find the canary value and thus defeat the mitigation, at which point local privilege escalation may be possible.

Record
CVE-2026-3038
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-787
Updated
2026-11-02
EUVDEUVD-2026-10334 7.5

The rtsock_msg_buffer() function serializes routing information into a buffer. As a part of this, it copies sockaddr structures into a sockaddr_storage structure on the stack. It assumes that the source sockaddr length field had already been validated, but this is not necessarily the case, and it's possible for a malicious userspace program to craft a request which triggers a 127-byte overflow.

In practice, this overflow immediately overwrites the canary for the rtsock_msg_buffer() stack frame, resulting in a panic once the function returns.

The bug allows an unprivileged user to crash the kernel by triggering a stack buffer overflow in rtsock_msg_buffer(). In particular, the overflow will corrupt a stack canary value that is verified when the function returns; this mitigates the impact of the stack overflow by triggering a kernel panic.

Other kernel bugs may exist which allow userspace to find the canary value and thus defeat the mitigation, at which point local privilege escalation may be possible.

Record
EUVD-2026-10334
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-jjxv-p5qr-w2hv 7.5

The rtsock_msg_buffer() function serializes routing information into a buffer. As a part of this...

The rtsock_msg_buffer() function serializes routing information into a buffer. As a part of this, it copies sockaddr structures into a sockaddr_storage structure on the stack. It assumes that the source sockaddr length field had already been validated, but this is not necessarily the case, and it's possible for a malicious userspace program to craft a request which triggers a 127-byte overflow.

In practice, this overflow immediately overwrites the canary for the rtsock_msg_buffer() stack frame, resulting in a panic once the function returns.

The bug allows an unprivileged user to crash the kernel by triggering a stack buffer overflow in rtsock_msg_buffer(). In particular, the overflow will corrupt a stack canary value that is verified when the function returns; this mitigates the impact of the stack overflow by triggering a kernel panic.

Other kernel bugs may exist which allow userspace to find the canary value and thus defeat the mitigation, at which point local privilege escalation may be possible.

Record
GHSA-jjxv-p5qr-w2hv
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-787
Updated
2026-11-02
NVD 7.5

The rtsock_msg_buffer() function serializes routing information into a buffer. As a part of this, it copies sockaddr structures into a sockaddr_storage structure on the stack. It assumes that the source sockaddr length field had already been validated, but this is not necessarily the case, and it's possible for a malicious userspace program to craft a request which triggers a 127-byte overflow.

In practice, this overflow immediately overwrites the canary for the rtsock_msg_buffer() stack frame, resulting in a panic once the function returns.

The bug allows an unprivileged user to crash the kernel by triggering a stack buffer overflow in rtsock_msg_buffer(). In particular, the overflow will corrupt a stack canary value that is verified when the function returns; this mitigates the impact of the stack overflow by triggering a kernel panic.

Other kernel bugs may exist which allow userspace to find the canary value and thus defeat the mitigation, at which point local privilege escalation may be possible.

Record
CVE-2026-3038
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-787
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-3038 is a high vulnerability (CVSS 7.5) in Freebsd, published March 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.65%, the 51st percentile. No source names a fixed version.

References

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