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NVD / CVE Program· CNA Linux

CVE-2026-53003: pppoe: drop PFC frames

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 0.71% (FIRST EPSS); higher than 53.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 0cab5d077dd1efd2bd1a47271acc35894f945b4f, 2b5c3c040d020e3ab3b9a8887031202d96843b1e, 49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.143.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0cab5d077dd1efd2bd1a47271acc35894f945b4f, 2b5c3c040d020e3ab3b9a8887031202d96843b1e, 49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.143.1-1 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: drop PFC frames RFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT RECOMMENDED for PPPoE. In practice, pppd does not support negotiating PFC for PPPoE sessions, and the current PPPoE driver assumes an uncompressed (2-byte) protocol field. However, the generic PPP layer function ppp_input() is not aware of the negotiation result, and still accepts PFC frames. If a peer with a broken implementation or an attacker sends a frame with a compressed (1-byte) protocol field, the subsequent PPP payload is shifted by one byte. This causes the network header to be 4-byte misaligned, which may trigger unaligned access exceptions on some architectures. To reduce the attack surface, drop PPPoE PFC frames. Introduce ppp_skb_is_compressed_proto() helper function to be used in both ppp_generic.c and pppoe.c to avoid open-coding.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Jun 24, 2026
Updated
Oct 19, 2026
EPSS
0.7% · 53th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.5
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
  • No public exploit code on record
  • A fix has been released

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

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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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.0 and later · before 5.10.258
  • linux linux kernel5.11 and later · before 5.15.209
  • linux linux kernel5.16 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.141
  • linux linux kernel6.7 and later · before 6.12.91
  • linux linux kernel6.13 and later · before 6.18.33
  • linux linux kernel6.19 and later · before 7.0.10

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

    • 5.0affected
    • 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 and later · before cb3beef35ab5e0c1afca9fd7648c6ae499786377affected · git
    • 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 and later · before ba758fdf1399f310b30098b6faa3fd043de47dd2affected · git
    • 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 and later · before fcca1df05322bb04e344dd1178b54b76a08eb7c3affected · git
    • 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 and later · before 8a5e840babc5c0fbd10c73728a13192347771ec6affected · git
    • 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 and later · before 49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71affected · git
    • 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 and later · before 0cab5d077dd1efd2bd1a47271acc35894f945b4faffected · git
    • 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 and later · before 2b5c3c040d020e3ab3b9a8887031202d96843b1eaffected · git
    • 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 and later · before cc1ff87bce1ccd38410ab10960f576dcd17db679affected · git
    • before 5.0not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.10-17.0.10-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-53001Jun 24, 2026 · netfilter: xtables: restrict several matches to inet family
    22Monitor
  • ← EarlierCVE-2026-53002Jun 24, 2026 · netfilter: conntrack: remove sprintf usage
    39Monitor
  • Later →CVE-2026-53005Jun 24, 2026 · af_unix: Drop all SCM attributes for SOCKMAP.
    31Monitor

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 Linux0cab5d077dd1efd2bd1a47271acc35894f945b4fVendor (CNA)
Linux Linux2b5c3c040d020e3ab3b9a8887031202d96843b1eVendor (CNA)
Linux Linux49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71Vendor (CNA)
Linux Linux8a5e840babc5c0fbd10c73728a13192347771ec6Vendor (CNA)
Linux Linuxba758fdf1399f310b30098b6faa3fd043de47dd2Vendor (CNA)
Linux Linuxcb3beef35ab5e0c1afca9fd7648c6ae499786377Vendor (CNA)
Linux Linuxcc1ff87bce1ccd38410ab10960f576dcd17db679Vendor (CNA)
Linux Linuxfcca1df05322bb04e344dd1178b54b76a08eb7c3Vendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.06.6.143.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.176-1 · 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.

  • CVE-2026-532211 days apartip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()
    39Monitor
  • CVE-2026-6403725 days apartwifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled
    39Monitor
  • CVE-2026-6404625 days apartnet: tls: prevent chain-after-chain in plain text SG
    39Monitor
  • CVE-2026-4611527 days apartblock: add pgmap check to biovec_phys_mergeable
    39Monitor
  • CVE-2026-4311449 days apartnetfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry
    37Monitor
  • CVE-2026-4626621 days apartinet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP
    36Monitor

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

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-20 · Improper Input Validation

CVSS vector

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

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