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NVD / CVE Program· CNA Linux

CVE-2026-68121: pppoe: reload header pointer after dev_hard_header()

Noroxi assessment

Priority: Monitor (action score 31/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.36% (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 6866abf59976d273164a6624234d96a967280223, 6eed5ae7887a93160803d2b81ff88e75eefd4a4c, 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 6866abf59976d273164a6624234d96a967280223, 6eed5ae7887a93160803d2b81ff88e75eefd4a4c, 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1 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: pppoe: reload header pointer after dev_hard_header() pppoe_sendmsg() saves a pointer to the PPPoE header before calling dev_hard_header(). Device header callbacks are allowed to reallocate the skb head, invalidating pointers into it. This can happen when a send is blocked in copy_from_user() while the first non-Ethernet port is added to an empty team device. The team's delegated GRE header callback then expands the skb head. PPPoE subsequently writes six bytes through the stale pointer into the freed head. Reload the PPPoE header through the skb's network-header offset after device header creation. pskb_expand_head() updates that offset when it relocates the head.

HighCVSS 7.8 · v3.1—Proof of concept Fix available
Published
Aug 10, 2026
Updated
Oct 19, 2026
EPSS
0.3% · 30th percentile

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 · 0.3%

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.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-68121

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 6eed5ae7887a93160803d2b81ff88e75eefd4a4caffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before ba3409369c5413cdf0dcbf3a928f76b48e8c3e6aaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e6493a4d1ee17595766165fa446d45b7e0c318d0affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 7e9fbd7f96bcde63a7c798fe16b38cedee7a1501affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 6866abf59976d273164a6624234d96a967280223affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before bed4caecd723693f750e13adbb2c42ca1249a3fdaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e9c238f6fe42fb1b4dba3a578277de32cb487937affected · git
    • before 2.6.12not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.60.1.el10_26.12.0-211.60.1.el10_2

+96

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-2026-68117Aug 10, 2026 · tipc: clear sock->sk on the failed-insert path in tipc_sk_create()
    39Monitor
  • ← EarlierCVE-2026-68118Aug 10, 2026 · tcp: challenge ACK for non-exact RST in SYN-RECEIVED
    32Monitor
  • Later →CVE-2026-68123Aug 10, 2026 · openvswitch: fix GSO userspace truncation underflow
    39Monitor

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 Linux6866abf59976d273164a6624234d96a967280223Vendor (CNA)
Linux Linux6eed5ae7887a93160803d2b81ff88e75eefd4a4cVendor (CNA)
Linux Linux7a56e7c9b08e08fd55a1bcada24cf4fe3782b722Vendor (CNA)
Linux Linux7e9fbd7f96bcde63a7c798fe16b38cedee7a1501Vendor (CNA)
Linux Linuxba3409369c5413cdf0dcbf3a928f76b48e8c3e6aVendor (CNA)
Linux Linuxbed4caecd723693f750e13adbb2c42ca1249a3fdVendor (CNA)
Linux Linuxe6493a4d1ee17595766165fa446d45b7e0c318d0Vendor (CNA)
Linux Linuxe9c238f6fe42fb1b4dba3a578277de32cb487937Vendor (CNA)
azl3 kernel 6.6.143.1-1 on Azure Linux 3.06.6.150.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:bpftool4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-abi-stablelists4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-core4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-cross-headers4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-core4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-devel4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules-extra4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-devel4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-doc4.18.0-553.168.1.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.101-1~deb12u1 · Debian:12Package registry (OSV)
red hat:bpftool0:4.18.0-553.168.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:bpftool-debuginfo0:4.18.0-553.168.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel0:4.18.0-553.168.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-abi-stablelists0:4.18.0-553.168.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-core0:4.18.0-553.168.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug0:4.18.0-553.168.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-core0:4.18.0-553.168.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)

+31

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02026-09-18
Proof-of-concept repository on GitHubstars:02026-09-19
Proof-of-concept repository on GitHubstars:02026-09-21

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. First PoC+38 d
  3. TodayNov 2, 2026+84 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

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.

  • CVE-2026-681170 days aparttipc: clear sock->sk on the failed-insert path in tipc_sk_create()
    39Monitor
  • CVE-2026-681270 days apartila: reload IPv6 header after pskb_may_pull in checksum adjust
    39Monitor
  • CVE-2026-681440 days apartphonet: pep: fix use-after-free in pep_get_sb()
    39Monitor
  • CVE-2026-681560 days apartlibceph: refresh auth->authorizer_buf{,_len} after authorizer update
    39Monitor
  • CVE-2026-683810 days apartksmbd: pin conn during async oplock break notification
    39Monitor
  • CVE-2026-684260 days apartxfrm: fix stale skb->prev after async crypto steals a GSO segment
    39Monitor

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

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)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

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 (7 more)

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

All records