EUVD-2026-39897
GHSA-mfj5-8wwq-98rr
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Local access only (AV:L), low privilege sufficient to create sockets (PR:L), no confidentiality or integrity impact, full availability loss via kernel panic (A:H).
Primary rating from NVD.
CVSS VectorNVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
5DescriptionNVD
In the Linux kernel, the following vulnerability has been resolved:
net: phonet: do not BUG_ON() in pn_socket_autobind() on failed bind
syzbot reported a kernel BUG triggered from pn_socket_sendmsg() via pn_socket_autobind():
kernel BUG at net/phonet/socket.c:213! RIP: 0010:pn_socket_autobind net/phonet/socket.c:213 [inline] RIP: 0010:pn_socket_sendmsg+0x240/0x250 net/phonet/socket.c:421 Call Trace: sock_sendmsg_nosec+0x112/0x150 net/socket.c:797 __sock_sendmsg net/socket.c:812 [inline] __sys_sendto+0x402/0x590 net/socket.c:2280 ...
pn_socket_autobind() calls pn_socket_bind() with port 0 and, on -EINVAL, assumes the socket was already bound and asserts that the port is non-zero:
err = pn_socket_bind(sock, ..., sizeof(struct sockaddr_pn)); if (err != -EINVAL) return err; BUG_ON(!pn_port(pn_sk(sock->sk)->sobject)); return 0; /* socket was already bound */
However pn_socket_bind() also returns -EINVAL when sk->sk_state is not TCP_CLOSE, even when the socket has never been bound and pn_port() is still 0. In that case the BUG_ON() fires and panics the kernel from a user-triggerable path.
Treat the "bind returned -EINVAL but pn_port() is still 0" case as a regular error and propagate -EINVAL to the caller instead of crashing. Existing callers already translate a non-zero return from pn_socket_autobind() into -ENOBUFS/-EAGAIN, so returning -EINVAL here only changes behaviour from panic to a normal errno.
AnalysisAI
Kernel panic via reachable assertion in the Linux kernel Phonet subsystem allows any low-privileged local user to crash the system. The flaw exists in pn_socket_autobind() at net/phonet/socket.c:213, where a BUG_ON() assertion fires when pn_socket_bind() returns -EINVAL for a reason other than an already-bound socket - specifically, when sk->sk_state is not TCP_CLOSE on an unbound socket. …
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
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires a local account on the target system with permission to create Phonet sockets (AF_PHONET), which is a standard unprivileged operation on kernels with CONFIG_PHONET compiled in or the phonet module loaded. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H aligns well with the description: local, low-privilege access is sufficient, there is no complexity barrier, and the impact is a complete availability loss (kernel panic). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A local user with standard shell access on a Phonet-enabled Linux system creates a Phonet socket and transitions it to a non-TCP_CLOSE state, then issues a sendmsg() call without first binding the socket. The kernel enters pn_socket_autobind(), which calls pn_socket_bind() - receiving -EINVAL due to the socket state rather than because the socket is already bound - and the BUG_ON() assertion fires, triggering an immediate kernel panic and crashing the entire system. … |
| Remediation | The upstream fix is available as stable-tree commits at https://git.kernel.org/stable/c/6db58ee730bf434d1afca91b91826e26688856ed and https://git.kernel.org/stable/c/5b0c911bcdbd982f7748d11c0b39ec5808eae2de; patched kernel versions per EUVD are 7.1 and 7.0.10. … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
Same weakness CWE-617 – Reachable Assertion
View allSame technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today