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

CVE-2026-98950: flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()

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: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a, 61b43a51a55929ec040bee3ea51af2121b956d05, c44c02c930c6583b235a1937c69ff716c4bb4514; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a, 61b43a51a55929ec040bee3ea51af2121b956d05, c44c02c930c6583b235a1937c69ff716c4bb4514; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes 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: flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect() bpf_flow_dissect() sanitizes the offsets returned by the BPF program with clamp_t(u16, ..., hlen). If hlen is bigger than 65535, the upper bound is truncated before the comparison. For instance, with hlen == 65536, both nhoff and thoff are forced to zero, even if the program returned sane values. This is the same class of bug as the one fixed in commit 99bda1ecbd56 ("flow_dissector: avoid u16 truncation of skb->len when computing thoff"). That fix does not cover the BPF path, because __skb_flow_dissect() returns early when a BPF flow dissector handles the packet. struct bpf_flow_keys stores nhoff and thoff as u16, so cap hlen to U16_MAX before clamping. Found by sashiko while reviewing the commit above.

—No exploit Fix available
Published
Oct 23, 2026
Updated
Oct 23, 2026
EPSS
0.1% · 7th 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

What does it mean in your environment?

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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

    • 4.20affected
    • d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 and later · before c44c02c930c6583b235a1937c69ff716c4bb4514affected · git
    • d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 and later · before 3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2aaffected · git
    • d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 and later · before cc18eb0e9941162c03f03f411ed7f6c339d91fa0affected · git
    • d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 and later · before 61b43a51a55929ec040bee3ea51af2121b956d05affected · git
    • d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 and later · before f202578efc738b883cfa04889eb97328914265a7affected · git
    • before 4.20not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver
    • 6.12.113 and later · up to and including 6.12.*not affected · semver
    • 6.18.57 and later · up to and including 6.18.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.11-17.2.11-1

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-2026-98948Oct 23, 2026 · mlxsw: spectrum_flower: Fix port range register leak in tmplt_create()
    0Monitor
  • ← EarlierCVE-2026-98949Oct 23, 2026 · drm/imagination: Fix reference and vm_bo handling in remap()
    0Monitor
  • Later →CVE-2026-98951Oct 23, 2026 · riscv: ptrace: Zero-initialize regset buffers before copyin
    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 Linux3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2aVendor (CNA)
Linux Linux61b43a51a55929ec040bee3ea51af2121b956d05Vendor (CNA)
Linux Linuxc44c02c930c6583b235a1937c69ff716c4bb4514Vendor (CNA)
Linux Linuxcc18eb0e9941162c03f03f411ed7f6c339d91fa0Vendor (CNA)
Linux Linuxf202578efc738b883cfa04889eb97328914265a7Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux6.12.113-1 · Debian:13Package 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. TodayOct 29, 2026+6 d
EPSS, last 120 days

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

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

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

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

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

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References

Show all references (4 more)

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

All records