VulnerabilityPublished 6 Oct 2026Updated 27 Oct 2026

CVE-2026-98372: Linux kernel · xfrm: iptfs: fix stack OOB read in iptfs_skb_reset_frag_walk()

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-98372· High

Not known to be exploited.

Data as of 28 Oct 2026, 01:28 UTC

Severity

High

Rated by Threat Radar · CVSS not yet scored by NVD

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-38.38 23 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1017.17 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1016.16 9 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 13 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1008.9 6 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: fix stack OOB read in iptfs_skb_reset_frag_walk() iptfs_skb_reset_frag_walk() advances to the fragment containing @offset with an unbounded loop: while (offset >= walk->past + walk->frags[walk->fragi].len) walk->past += walk->frags[walk->fragi++].len; walk->fragi is advanced and walk->frags[walk->fragi] is dereferenced without ever checking fragi against walk->nr_frags. When the requested offset is at or beyond the total length spanned by the walk's fragments, fragi runs past nr_frags and off the end of the fixed-size on-stack frags[MAX_SKB_FRAGS + 1] array, reading out-of-bounds stack memory. The two callers behave differently: iptfs_skb_add_frags() already guards against this with if (!walk->nr_frags || offset >= walk->total + walk->initial_offset) return len; but iptfs_skb_can_add_frags() has no such guard and calls iptfs_skb_reset_frag_walk() unconditionally, so it performs the out-of-range walk. Its own "fragi < walk->nr_frags" bound check runs only afterwards, too late to prevent the read. This is reachable from the receive path: a crafted IP-TFS (AGGFRAG) payload delivered to an IPTFS SA drives iptfs_reassem_cont() -> iptfs_skb_can_add_frags() with an offset past the fragment total, e.g.: BUG: KASAN: stack-out-of-bounds in iptfs_skb_reset_frag_walk+0x235/0x250 Read of size 4 at addr ffff888008ad7210 by task repro/345 iptfs_skb_reset_frag_walk+0x235/0x250 net/xfrm/xfrm_iptfs.c:392 iptfs_skb_can_add_frags+0x155/0x310 net/xfrm/xfrm_iptfs.c:420 iptfs_reassem_cont+0xcf8/0x1140 net/xfrm/xfrm_iptfs.c:902 iptfs_input_ordered+0x552/0x670 net/xfrm/xfrm_iptfs.c:1280 iptfs_input+0x3d6/0xde0 net/xfrm/xfrm_iptfs.c:1741 xfrm_input+0x282f/0x6140 net/xfrm/xfrm_input.c:700 xfrm4_esp_rcv+0x93/0x120 net/ipv4/xfrm4_protocol.c:104 ip_rcv+0x278/0x2d0 net/ipv4/ip_input.c:612 Give iptfs_skb_can_add_frags() the same up-front guard that iptfs_skb_add_frags() already has, so the walk is never entered with an out-of-range offset. When it triggers, the caller falls back to the existing linearize-and-copy path, which is safe.

References

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