CVE-2026-80303

MEDIUMPre-NVD 6.26.2
EchelonGraph scoreHIGH confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 6.2 from GitHub Security Advisory (severity: MODERATE) published 2026-11-06. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory

Also known asEUVD-2026-118328 (ENISA EUVD) · GHSA-2q9r-4cp6-374g (GitHub Security Advisories)Source: ENISA EUVD

6.2EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 6.2Exploit: None knownExposed services: Not assessed

Upgrade to version 26.7 or later to remediate this issue (from the CVE record's solution, Gen Digital Inc.) — apply it.

An integer underflow vulnerability in the Avast Windows Filtering Platform (WFP) stream parser on Windows allows denial of service by causing a system crash.

The WFP callout driver processes network stream data and computes length values for packet fragment reassembly. The length calculation does not properly validate input stream sizes against expected boundaries. When processing specially crafted input, the length computation underflows, resulting in allocation or buffer access with an extremely large wrapped-around size value.

The underflow can be triggered remotely via network traffic destined for the filtered port, or locally via crafted data provided to the filtering interface. The resulting memory allocation failure or out-of-bounds access causes a kernel panic and system crash.

CVSS v3
6.2
EG Score
6.2MEDIUMhigh confidence
EG Risk
28
EG Risk 28/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity62% × 45%
Impact severity (EG Severity): CVSS 6.2 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: Upgrade to version 26.7 or later to remediate this issue (from the CVE record's solution, Gen Digital Inc.). Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
2nd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.2): severity, escalated by confirmed exploitation. This CVE's 6.2 is its impact severity (EG Severity), not escalated.

EG Severity
6.2 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

Upgrade to version 26.7 or later to remediate this issue (from the CVE record's solution, Gen Digital Inc.). Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

November 6, 2026

Last Modified

November 12, 2026

Advisory Details (4)

Auto-updated Nov 12, 2026
Fix named in the CVE record's solution (Gen Digital Inc.).
Web pageMentions a patch (unverified)

Gen™ Security Advisories | Gen™ | Gen™

https://www.gendigital.com/us/en/contact-us/security-advisories/
Web page

How to update Avast Antivirus or Avast One | Avast

https://support.avast.com/en-us/article/Update-Antivirus

Vendor Advisories for CVE-2026-80303(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 15× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-13 16:57 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  2. 2026-11-12 22:31 UTCEchelonGraph re-scored
  3. 2026-11-12 22:31 UTCGHSA enrichmentGHSA-2q9r-4cp6-374g · GitHub severity MODERATE · GitHub CVSS 6.2
  4. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  5. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  6. 2026-11-10 19:39 UTCGHSA enrichmentGHSA-2q9r-4cp6-374g
  7. 2026-11-10 19:21 UTCEchelonGraph re-scoredFirst assessed: 6.2 MEDIUM
  8. 2026-11-10 19:21 UTCGHSA enrichmentGHSA-2q9r-4cp6-374g
  9. 2026-11-10 19:20 UTCMITRE cvelistV5CVSS v3 → 6.2 · severity → MEDIUM
  10. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  11. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  12. 2026-11-08 16:41 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  13. 2026-11-08 09:01 UTCEchelonGraph re-scored
  14. 2026-11-08 09:01 UTCGHSA enrichmentGHSA-2q9r-4cp6-374g
  15. 2026-11-07 16:40 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  16. 2026-11-06 17:04 UTCENISA EUVD ID recordedEUVD-2026-118328 · Source: ENISA EUVD
  17. 2026-11-06 16:27 UTCNVD update
  18. 2026-11-06 16:14 UTCEchelonGraph re-scored
  19. 2026-11-06 16:12 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-80303?
CVE-2026-80303 is a medium-severity vulnerability; its CVE record was published on November 6, 2026. An integer underflow vulnerability in the Avast Windows Filtering Platform (WFP) stream parser on Windows allows denial of service by causing a system crash. The WFP callout driver processes network stream data and computes length values for packet fragment reassembly. The length calculation does…
When was the CVE record for CVE-2026-80303 published?
The CVE record for CVE-2026-80303 was published on November 6, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 12, 2026; the record at its source may have been updated since.
Is CVE-2026-80303 actively exploited?
CVE-2026-80303 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (2nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-80303?
CVE-2026-80303 has a CVSS v3.1 base score of 6.2 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-80303?
The CVE record's solution for CVE-2026-80303, written by its CNA Gen Digital Inc., names the fix: "Upgrade to version 26.7 or later to remediate this issue." The vendor advisories EchelonGraph has for CVE-2026-80303 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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