Out-of-bounds Read in The Tcpdump Group Libpcap
CVE-2026-0799
In BPF instructions that load/store a value from/to a scratch memory register the register index is an unsigned 32-bit integer and must not exceed 15, but libpcap BPF interpreter does not validate the value. In particular uncommon use cases a crafted filter program can cause the interpreter to try reading and writing the OS process memory in the 16GiB starting at the current stack frame on 64-bit architectures and in the entire address space on 32-bit architectures.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H.
EPSS exploit prediction
EPSS: 0.001 (1.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000
Affected products
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-0799?
- CVE-2026-0799 is a high-severity vulnerability in The Tcpdump Group Libpcap, classified under Out-of-bounds Read. CVSS score: 8.7/10. Published 2026-09-05.
- How severe is CVE-2026-0799?
- High severity. CVSS v3 base score is 8.7 out of 10.