PatchTheCVECVE-2026-99077: In the Linux kernel, the following vulnerability has been resolved: ipv4: udp: Create exceptions before socke
CVE-2026-99077 is a high-severity flaw (CVSS 7.4) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
In the Linux kernel, the following vulnerability has been resolved: ipv4: udp: Create exceptions before socket matching Currently, when ICMP Fragmentation Needed and Redirect Message packets are locally delivered and quote a UDP packet, a FIB nexthop exception (FNHE) is only created if the kernel can match the UDP packet to an existing socket. This behavior allows off-path attackers to conduct a side-channel attack on the FNHE cache in order t
Why this priority
- High severity
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.4 (High) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.2% (top 89%) |
| CISA exploited list | No |
| Published | 2026-10-23 |
| Last modified | 2026-10-24 |
Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Advisories and coverage
Official advisories
- Linux Kernel CVE Announce: CVE-2026-99077: ipv4: udp: Create exceptions before socket matching 2026-10-23
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-2026-99077?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-99077 being exploited?
CVE-2026-99077 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-2026-99077 affect?
CVE-2026-99077 affects affected software. Severity is high (CVSS 7.4). In the Linux kernel, the following vulnerability has been resolved: ipv4: udp: Create exceptions before socket matching Currently, when ICMP Fragmentation Needed and Redirect Message packets are locally delivered and quote a UDP packet, a
How urgent is CVE-2026-99077?
Priority 39/100. High severity; Remotely exploitable, no login, no user action; On your watchlist