PatchTheCVECVE-2026-79980: The DHCPv4 client in subsys/net/lib/dhcpv4/dhcpv4.c maintained its transaction identifier (iface->config.dhcpv
CVE-2026-79980 is a medium-severity flaw (CVSS 5.6) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
The DHCPv4 client in subsys/net/lib/dhcpv4/dhcpv4.c maintained its transaction identifier (iface->config.dhcpv4.xid) as a counter rather than as a per-transaction random value. It was seeded once with sys_rand32_get() in dhcpv4_start_internal(), incremented by one in dhcpv4_send_discover() and dhcpv4_send_decline(), and never changed by dhcpv4_send_request() — so every RENEWING and REBINDING exchange reused, unchanged, the identifier that had alr
Why this priority
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 5.6 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.3% (top 81%) |
| CISA exploited list | No |
| Weakness | CWE-340 |
| Published | 2026-10-23 |
| Last modified | 2026-10-23 |
Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-79980?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-79980 being exploited?
CVE-2026-79980 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-79980 affect?
CVE-2026-79980 affects affected software. Severity is medium (CVSS 5.6). The DHCPv4 client in subsys/net/lib/dhcpv4/dhcpv4.c maintained its transaction identifier (iface->config.dhcpv4.xid) as a counter rather than as a per-transaction random value. It was seeded once with sys_rand32_get() in dhcpv4_start_intern
How urgent is CVE-2026-79980?
Priority 29/100. Remotely exploitable, no login, no user action