# CVE-2026-98372: Linux kernel stack out-of-bounds read in xfrm iptfs

Source: https://junglewise.ai/threats/cve-2026-98372-in-the-linux-kernel-the-following-vulnerability-has-been-resolved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-06. Updated: 2026-10-06  
License: CC BY 4.0 with a link back

CVE-2026-98372 · Severity: info · Published 2026-10-06

The Linux kernel's IP-TFS (IP-based Tunnel Fragmentation and Serialization) implementation contains a stack memory read vulnerability. A remote attacker can send a crafted network packet to trigger an out-of-bounds read of kernel stack memory on systems using IPTFS encryption. This could leak sensitive kernel data, though exploitation for remote code execution is unlikely with this specific issue.

Technologies: [Linux Kernel](https://junglewise.ai/threats/technologies/kernel). Vendors: [Linux](https://junglewise.ai/threats/vendors/linux).

## Quick answers

**Is CVE-2026-98372 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-98372 being exploited in the wild.

**How severe is CVE-2026-98372?** Informational severity, published 6 October 2026.

**Which products and versions are affected?** Linux Kernel Versions with xfrm iptfs implementation (4.20+).

**Is there a fix for CVE-2026-98372?** No fixed version is recorded yet. Add an up-front bounds check in iptfs_skb_can_add_frags() before calling iptfs_skb_reset_frag_walk(), matching the existing guard in iptfs_skb_add_frags() to reject out-of-range offsets early. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-98372 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-98372?** Check whether you run Linux Kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix


Add an up-front bounds check in iptfs_skb_can_add_frags() before calling iptfs_skb_reset_frag_walk(), matching the existing guard in iptfs_skb_add_frags() to reject out-of-range offsets early.

## Technical details

The vulnerability is a stack out-of-bounds read in the iptfs_skb_reset_frag_walk() function in net/xfrm/xfrm_iptfs.c. An unbounded loop advances through fragment indices without checking against the fragment count limit, allowing reads past a fixed-size on-stack array. The issue is reachable from the network receive path when processing IP-TFS (AGGFRAG) packets with offsets exceeding the total fragment span, triggered via iptfs_reassem_cont() -> iptfs_skb_can_add_frags().

## Affected products

- Linux Linux kernel Versions with xfrm iptfs implementation (4.20+)

## Timeline

- 2026-10-06: advisory: Vulnerability disclosed and patched in mainline kernel

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