CVE-2026-98077
Received Received - Intake

Buffer Overflow in Linux Kernel Netfilter SIP Module

Vulnerability report for CVE-2026-98077, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-25

Last updated on: 2026-09-25

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: fix OOB read in sip_skip_whitespace() sip_skip_whitespace() returns dptr unchanged when its own loop exhausts the buffer (dptr == limit), instead of NULL like its sibling sip_follow_continuation() returns on its own "no more data" path. ct_sip_get_header() only checks for NULL after calling it: dptr = sip_skip_whitespace(dptr, limit); if (dptr == NULL) break; if (*dptr != ':' || ++dptr >= limit) break; so a recognized header name followed only by spaces/tabs running to the exact end of the SIP payload, with no colon, makes the very next statement read one byte past the buffer. Make both "no more data" outcomes return NULL, matching the convention sip_follow_continuation() already uses and that both existing callers already check for.

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Meta Information

Published
2026-09-25
Last Modified
2026-09-25
Generated
2026-09-25
AI Q&A
2026-09-25
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel linux_kernel *

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a buffer overflow vulnerability in the Linux kernel's netfilter SIP connection tracking module. It occurs when parsing SIP headers with excessive whitespace at the end of the payload. The function sip_skip_whitespace() fails to return NULL when it reaches the buffer limit, causing subsequent code to read one byte past the buffer.

Detection Guidance

This vulnerability is specific to the Linux kernel's SIP connection tracking module. Detection requires checking kernel logs for crashes or memory corruption related to SIP packet processing. Monitor for kernel oops messages or system crashes when handling SIP traffic. Use commands like 'dmesg | grep -i sip' or 'journalctl -k | grep -i sip' to search for related errors.

Impact Analysis

This vulnerability could allow an attacker to crash the system or potentially execute arbitrary code with kernel privileges. It affects systems using the Linux kernel with SIP connection tracking enabled, which may be used in VoIP or network security applications.

Mitigation Strategies

Apply the latest kernel security patches from your Linux distribution. If patches are unavailable, disable SIP connection tracking in netfilter by removing or blocking SIP-related rules in iptables/nftables. Restrict SIP traffic to trusted sources only. Monitor network traffic for unusual SIP packet patterns.

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