infinte loop in libpcap before 1.10.7

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-6554
StatePUBLISHED
AssignerTcpdump
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-05 19:16:56 UTC
Updated2026-10-22 21:17:21 UTC
Descriptionlibpcap BPF interpreter treats the offset in the 'ja L' BPF instruction as a signed integer to implement looping via backward jumps, but it does not limit the number of loop iterations. A crafted filter program or the 'protochain' primitive used on a crafted network packet can cause the interpreter to loop infinitely.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.001050000 probability, percentile 0.010210000 (date 2026-10-22)

Problem Types: CWE-835 | CWE-835 CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA The Tcpdump Group Libpcap affected 1.10.7 semver Not specified

References

ReferenceSourceLinkTags
www.openwall.com/lists/oss-security/2026/10/22/3 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
github.com/the-tcpdump-group/libpcap/commit/ff3c83475ac303c6b681c52ad0b6... [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Kaixuan LI has discovered the crafted filter program attack vector (en)

CNA: Denis Ovsienko has discovered the 'protochain' attack vector (en)

Additional Advisory Data

Solutions

CNA: Upgrade to libpcap 1.10.7.

Workarounds

CNA: Do not use filter programs that have been compiled outside of libpcap. Build libpcap without the 'protochain' primitive support.

Exploits

CNA: Functional exploits exist for both attack vectors.

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