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NVD / CVE Program· CNA Linux

CVE-2026-80731: net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.14% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 3.17, 3.2.81, 3b9a324e646d3657a8d9806dfbfe4f3e4066e882; azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 6.6.152.1-1.

Low priority for now. Upgrade to Linux Linux 3.17, 3.2.81, 3b9a324e646d3657a8d9806dfbfe4f3e4066e882; azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 6.6.152.1-1 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: net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header dev_validate_header() reads dev->hard_header_len directly when zero-padding short link layer headers for CAP_SYS_RAWIO holders: if (capable(CAP_SYS_RAWIO)) { memset(ll_header + len, 0, dev->hard_header_len - len); return true; } Packet send paths call dev_validate_header() on skbs whose headroom was allocated from an earlier hard_header_len read. If the device is reconfigured so that dev->hard_header_len increases before validation, the memset writes past the reserved buffer, an out-of-bounds write. This out-of-bounds write is masked in some SOCK_RAW paths today because the same concurrent increase can first make skb_push() exceed the reserved headroom and trigger skb_under_panic(). Remove the zero-padding branch before making those hard_header_len reads consistent, so the snapshot fixes do not turn a loud panic into a silent overwrite. This path is only reached for variable length L2 protocols, where len < hard_header_len but len >= min_header_len. No remaining in-tree variable length L2 protocol implements header_ops->validate, and the CAP_SYS_RAWIO bypass that zero-pads and accepts short headers has no real value beyond allowing testing of intentionally malformed input. Drop the CAP_SYS_RAWIO branch. The remaining reads of dev->hard_header_len in dev_validate_header() are comparisons only and have no memory safety impact.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Sep 3, 2026
Updated
Oct 16, 2026
EPSS
0.1% · 3th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • No public exploit code on record
  • A fix has been released

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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

    • f58a6c08ebdfa978178bbca78c2ba744a2665912, 1df16498dfd0d5a129bdf2982d9a08df73e8923d, 8b8d278aa4de9335682bbd4a3bb619af015c859e, 6804052fa9d86e9a512c88b24a5debbfc1a490fc, 4.6affected
    • b5518429e70cd783b8ca52335456172c1a0589f6 and later · before 53fd7f912c0877647d6a1e1877f5ea8535ee0b4aaffected · git
    • 2793a23aacbd754dbbb5cb75093deb7e4103bace and later · before fa6d98dd925e72fc028b26a0cbbff9d2f0601ff6affected · git
    • 2793a23aacbd754dbbb5cb75093deb7e4103bace and later · before 8fc9816404166a90ed8d544dc52482fafffb6d9faffected · git
    • 2793a23aacbd754dbbb5cb75093deb7e4103bace and later · before b0f92a5731dc82556a9ae005cc35f71ab136307baffected · git
    • 2793a23aacbd754dbbb5cb75093deb7e4103bace and later · before 99df6b7a713f96eda206680d100b76e15f9d9b69affected · git
    • 2793a23aacbd754dbbb5cb75093deb7e4103bace and later · before 74e035f07f53feca09e2352e77fccb09cad5e208affected · git
    • 2793a23aacbd754dbbb5cb75093deb7e4103bace and later · before dbb30dc943a93e083f1e531bfdc6779e57de40d0affected · git
    • 2793a23aacbd754dbbb5cb75093deb7e4103bace and later · before fc902f52a02298c7432b2334c0c82a2885a1a8b6affected · git
    • 2793a23aacbd754dbbb5cb75093deb7e4103bace and later · before 3b9a324e646d3657a8d9806dfbfe4f3e4066e882affected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:12linux-6.12before 6.12.107-1~deb12u16.12.107-1~deb12u1
Debian:13linuxbefore 6.12.105-16.12.105-1
Debian:14linuxbefore 7.1.9-17.1.9-1

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-2026-80728Sep 3, 2026 · Revert "drm/amdgpu: fix aperture mapping leak"
    0Monitor
  • ← EarlierCVE-2026-80729Sep 3, 2026 · mm/huge_memory: initialise workingset state before folio split
    0Monitor
  • Later →CVE-2026-80733Sep 3, 2026 · net: remove WARN_ON_ONCE() from sk_mc_loop()
    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 Linux3.17Vendor (CNA)
Linux Linux3.2.81Vendor (CNA)
Linux Linux3b9a324e646d3657a8d9806dfbfe4f3e4066e882Vendor (CNA)
Linux Linux4.2Vendor (CNA)
Linux Linux4.5Vendor (CNA)
Linux Linux4.6Vendor (CNA)
Linux Linux53fd7f912c0877647d6a1e1877f5ea8535ee0b4aVendor (CNA)
Linux Linux74e035f07f53feca09e2352e77fccb09cad5e208Vendor (CNA)
Linux Linux8fc9816404166a90ed8d544dc52482fafffb6d9fVendor (CNA)
Linux Linux99df6b7a713f96eda206680d100b76e15f9d9b69Vendor (CNA)
Linux Linuxb0f92a5731dc82556a9ae005cc35f71ab136307bVendor (CNA)
Linux Linuxdbb30dc943a93e083f1e531bfdc6779e57de40d0Vendor (CNA)
Linux Linuxfa6d98dd925e72fc028b26a0cbbff9d2f0601ff6Vendor (CNA)
Linux Linuxfc902f52a02298c7432b2334c0c82a2885a1a8b6Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.06.6.152.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.107-1~deb12u1 · Debian:12Package 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.

No dated events beyond publication.

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

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

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. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (8 more)

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

All records