CVE-2026-31911: CWE-617 Reachable Assertion in The Tcpdump Group libpcap
Description
CVE-2026-31911 is a medium severity vulnerability in libpcap's BPF interpreter where an invalid opcode in a crafted filter program causes the process to abort. This results in a reachable assertion that terminates the OS process running libpcap. No confidentiality or integrity impact is reported, only availability is affected.
CVSS v3.1
Score 5.5medium
Affected software
The Tcpdump Group
libpcap
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Tcpdump Group's libpcap contains a vulnerability (CVE-2026-31911) in its BPF interpreter. When the interpreter encounters a BPF instruction with an invalid opcode, it calls abort(), causing the process to terminate unexpectedly. This can be triggered by a specially crafted filter program in uncommon use cases. The vulnerability affects libpcap versions from 0 up to but not including 1.10.7. The CVSS 3.1 base score is 5.5, reflecting a local attack vector with low complexity and no user interaction, impacting availability only.
Potential Impact
Exploitation of this vulnerability causes the libpcap process to abort, leading to denial of service (availability impact) on the affected system. There is no impact on confidentiality or integrity. The attack requires local access with low privileges and no user interaction.
Mitigation Recommendations
No official patch or fix is currently referenced. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid running untrusted or crafted BPF filter programs that could trigger invalid opcodes in libpcap.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Tcpdump
- Date Reserved
- 2026-03-10T09:30:50.972Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a9c688aacd9273b49460ebc
Added to database: 09/05/2026, 19:07:54 UTC
Last enriched: 09/15/2026, 01:02:02 UTC
Last updated: 10/19/2026, 06:48:16 UTC
Views: 92
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