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NVD / CVE Program· CNA Linux

CVE-2026-63868: net: garp: fix unsigned integer underflow in garp_pdu_parse_attr

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.12% (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 04e22fefac1af3e32f245e9045382348773b5d59, 16e408e607a94b646fb14a2a98422c6877ae4b3c, 29f28172afb2ae7b31e9bf3e978396f20b381688.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 04e22fefac1af3e32f245e9045382348773b5d59, 16e408e607a94b646fb14a2a98422c6877ae4b3c, 29f28172afb2ae7b31e9bf3e978396f20b381688 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: garp: fix unsigned integer underflow in garp_pdu_parse_attr The receive-side GARP attribute parser computes dlen with reversed operands: dlen = sizeof(*ga) - ga->len; ga->len is the on-wire attribute length and includes the GARP attribute header. For normal attributes with data, ga->len is larger than sizeof(*ga), so the subtraction underflows in unsigned arithmetic. The resulting value is later passed to garp_attr_lookup(), whose length argument is u8. After truncation, the parsed data length usually no longer matches the length stored for locally registered attributes, so received Join/Leave events are ignored. This breaks the GARP receive path for common attributes, such as GVRP VLAN registration attributes. Compute the data length as the attribute length minus the header length.

Published
Jul 19, 2026
Updated
Nov 6, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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.

Follow CVE-2026-63868

When you'll hear from us

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  • 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

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

    • 2.6.27affected
    • eca9ebac651f774d8b10fce7c5d173c3c3d3394f and later · before 29f28172afb2ae7b31e9bf3e978396f20b381688affected · git
    • eca9ebac651f774d8b10fce7c5d173c3c3d3394f and later · before 973cf7c433d27f4d9556d0b7c332543be7ed7a6eaffected · git
    • eca9ebac651f774d8b10fce7c5d173c3c3d3394f and later · before d8dcd14aa886b8effd83022c550669f4f262854baffected · git
    • eca9ebac651f774d8b10fce7c5d173c3c3d3394f and later · before 74e02121be1dcc0efcd56ebdf0171d6129105659affected · git
    • eca9ebac651f774d8b10fce7c5d173c3c3d3394f and later · before d4c86ea09ae3e63ee5aa86e941fcc38e0e39874aaffected · git
    • eca9ebac651f774d8b10fce7c5d173c3c3d3394f and later · before 04e22fefac1af3e32f245e9045382348773b5d59affected · git
    • eca9ebac651f774d8b10fce7c5d173c3c3d3394f and later · before a11f1a671b1361f0f1278dc0041374f2730df73faffected · git
    • eca9ebac651f774d8b10fce7c5d173c3c3d3394f and later · before 16e408e607a94b646fb14a2a98422c6877ae4b3caffected · git
    • before 2.6.27not affected · semver
Affected versions · NVD (8)

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

  • linux linux kernel2.6.27 and later · before 5.10.259
  • linux linux kernel5.11 and later · before 5.15.210
  • linux linux kernel5.16 and later · before 6.1.176
  • linux linux kernel6.2 and later · before 6.6.143
  • linux linux kernel6.7 and later · before 6.12.94
  • linux linux kernel6.13 and later · before 6.18.36
  • linux linux kernel6.19 and later · before 7.0.13
  • linux linux kernel7.1

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 7.0.13-17.0.13-1

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-2026-63866Jul 19, 2026 · wifi: mt76: mt7996: Clear wcid pointer in mt7996_mac_sta_deinit_link()
    35Monitor
  • ← EarlierCVE-2026-63867Jul 19, 2026 · mptcp: close TOCTOU race while computing rcv_wnd
    32Monitor
  • Later →CVE-2026-63869Jul 19, 2026 · wifi: mac80211: limit injected antenna index in ieee80211_parse_tx_radiotap
    30Monitor

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 Linux04e22fefac1af3e32f245e9045382348773b5d59Vendor (CNA)
Linux Linux16e408e607a94b646fb14a2a98422c6877ae4b3cVendor (CNA)
Linux Linux29f28172afb2ae7b31e9bf3e978396f20b381688Vendor (CNA)
Linux Linux74e02121be1dcc0efcd56ebdf0171d6129105659Vendor (CNA)
Linux Linux973cf7c433d27f4d9556d0b7c332543be7ed7a6eVendor (CNA)
Linux Linuxa11f1a671b1361f0f1278dc0041374f2730df73fVendor (CNA)
Linux Linuxd4c86ea09ae3e63ee5aa86e941fcc38e0e39874aVendor (CNA)
Linux Linuxd8dcd14aa886b8effd83022c550669f4f262854bVendor (CNA)
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).

Variant candidates

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

  • CVE-2026-5317624 days apartIB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN
    39Monitor
  • CVE-2026-639400 days apartKVM: SEV: Ignore Port I/O requests of length '0'
    37Monitor
  • CVE-2026-644676 days apartrust_binder: use a u64 stride when cleaning up the offsets array
    35Monitor
  • CVE-2026-4318774 days apartxfs: delete attr leaf freemap entries when empty
    35Monitor
  • CVE-2026-5317824 days apartstaging: rtl8723bs: rtw_mlme: add bounds checks before ie_length subtraction
    32Monitor
  • CVE-2026-643616 days aparthfs/hfsplus: fix u32 overflow in check_and_correct_requested_length
    31Monitor

National notice (Türkiye Cybersecurity Directorate / USOM)

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

All national notices →

Not on record for this CVE: patch commit or PR link · researcher credit · public bounty program.

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

Weakness class (CWE)

CWE-191 · Integer Underflow (Wrap or Wraparound)

CVSS vector

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

nvd-primary

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. CVSS— → 5.5
  3. Severity— → medium
  4. 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