SB2026092834 - Out-of-bounds write in Linux kernel net ppp driver

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-98158)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper handling of skb headroom in ppp_async's process_input_packet() when processing a bad-FCS PPP frame followed by a crafted frame. A remote attacker can send malformed PPP frames to cause a denial of service.

When CCP compression is enabled, decompression can read before the skb head.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/0c53eb14975f029abd6b26896a460f0d2aaefe6b
• https://git.kernel.org/stable/c/717137221c7d90e7c98bda9a370c9da6cbf015e5
• https://git.kernel.org/stable/c/8dc5d98a16fa23c00999aecf10018c9f69fa5bf4
• https://git.kernel.org/stable/c/d0fc3dabfe67caf084e7119ceb2ee23f5ad2f2da