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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98371: xfrm: iptfs: fix runt reassembly panic from short inner tot_len

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Fixed version: Linux Linux 5b8afb56ccb7c014b0f1ac40341708b200443c2d, a7018ee0ea8622ed59edc064be4e0f2c26464f53, dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c.

Low priority for now. Upgrade to Linux Linux 5b8afb56ccb7c014b0f1ac40341708b200443c2d, a7018ee0ea8622ed59edc064be4e0f2c26464f53, dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: fix runt reassembly panic from short inner tot_len When the start of an inner packet is split across two outer packets such that fewer than 4 bytes land at the end of the first one, __input_process_payload() saves those bytes as a runt and skips the iplen/iphlen validation performed for in-place packets. When the continuation packet arrives, iptfs_reassem_cont() only requires the declared inner length to be >= sizeof(ra_runt) (6) before allocating the reassembly skb with that attacker-controlled length. However, __iptfs_iphlen() always returns the fixed minimum IP header size (20 for IPv4, 40 for IPv6), so for an inner IPv4 tot_len in [6, 19] the header-completion copy writes past the declared packet length, and the subsequent "ipremain -= copylen" underflows to ~4GB, leaving the payload copy length bounded only by blkoff (up to 64KB). At runtime the skb_put() tailroom check turns this into skb_over_panic(), i.e. an unprivileged kernel panic (DoS), reachable locally via userns+netns IPTFS SAs and remotely against IPTFS VPN gateways when the decrypted outer skb is linear (e.g. AF_PACKET taps, tun/tap delivery). Align the runt path with the normal path by requiring the declared inner length to cover at least the IP header size. This also subsumes the previous >= sizeof(ra_runt) check, since the minimum IP header is always larger than the runt buffer. This issue was found by the autokbug dynamic kernel fuzzer at Tencent Yunding Lab.

—No exploit Fix available
Published
Oct 6, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.14affected
    • 07569476544681816335099929ff3494dfbf6b05 and later · before a7018ee0ea8622ed59edc064be4e0f2c26464f53affected · git
    • 07569476544681816335099929ff3494dfbf6b05 and later · before 5b8afb56ccb7c014b0f1ac40341708b200443c2daffected · git
    • 07569476544681816335099929ff3494dfbf6b05 and later · before dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8caffected · git
    • before 6.14not affected · semver
    • 6.18.54 and later · up to and including 6.18.*not affected · semver
    • 7.2.8 and later · up to and including 7.2.*not affected · semver
    • 7.3 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:14linuxbefore 7.2.8-17.2.8-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-98369Oct 6, 2026 · xfrm: add missing rcu_read_lock(), skb_dst_force() and dev_hold() for xfrm_trans_reinject()
    31Monitor
  • ← EarlierCVE-2026-98370Oct 6, 2026 · xfrm: fix compat ALLOCSPI request use-after-free
    0Monitor
  • Later →CVE-2026-98372Oct 6, 2026 · xfrm: iptfs: fix stack OOB read in iptfs_skb_reset_frag_walk()
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux5b8afb56ccb7c014b0f1ac40341708b200443c2dVendor (CNA)
Linux Linuxa7018ee0ea8622ed59edc064be4e0f2c26464f53Vendor (CNA)
Linux Linuxdc33262be1fe43d0eb0b84fb58c6ed42e2f64a8cVendor (CNA)
debian:linux7.2.8-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 9, 2026+34 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

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No commit or PR link among the references.

Credits

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

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Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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