An integer underflow vulnerability exists in the `nextstate()` function in `gpsd/packet.c` of gpsd versions prior to commit `ffa1d6f40bca0b035fc7f5e563160ebb67199da7`. When parsing a NAVCOM packet, the payload length is calculated using `lexer->length = (size_t)c - 4` without checking if the input byte `c` is less than 4. This results in an unsigned integer underflow, setting `lexer->length` to a very large value (near `SIZE_MAX`). The parser then enters a loop attempting to consume this massive number of bytes, causing 100% CPU utilization and a Denial of Service (DoS) condition.
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Fixes

Solution

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Workaround

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History

Sat, 03 Jan 2026 00:15:00 +0000

Type Values Removed Values Added
Title gpsd: gpsd: Denial of Service due to malformed NAVCOM packet parsing
Weaknesses CWE-191
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Important


Fri, 02 Jan 2026 16:00:00 +0000

Type Values Removed Values Added
Description An integer underflow vulnerability exists in the `nextstate()` function in `gpsd/packet.c` of gpsd versions prior to commit `ffa1d6f40bca0b035fc7f5e563160ebb67199da7`. When parsing a NAVCOM packet, the payload length is calculated using `lexer->length = (size_t)c - 4` without checking if the input byte `c` is less than 4. This results in an unsigned integer underflow, setting `lexer->length` to a very large value (near `SIZE_MAX`). The parser then enters a loop attempting to consume this massive number of bytes, causing 100% CPU utilization and a Denial of Service (DoS) condition.
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-01-02T15:49:05.691Z

Reserved: 2025-12-08T00:00:00.000Z

Link: CVE-2025-67269

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-01-02T16:17:01.100

Modified: 2026-01-02T16:45:26.640

Link: CVE-2025-67269

cve-icon Redhat

Severity : Important

Publid Date: 2026-01-02T00:00:00Z

Links: CVE-2025-67269 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses