vciy

CVE-2023-28807

INDEX BUILT · 2026-09-20

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Bypass of ZIA domain fronting detection module through evasion technique

CVE-2023-288074 of 4 sources documented this
21

rank 21 = 0 + 19 + 0 + 2 + 0

rank@v1 · backlog

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.00345  ·  without this subject the record ranks 21

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 7.5, from NVD  ·  without this subject the record ranks 2

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

no persisting rise in 365 days  ·  without this subject the record ranks 21

How much of the world it touches

NVD CPE configurations

1 product in the CPE ranges  ·  without this subject the record ranks 19

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 21

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$7,370over the next 30 days, if this record is yours
Movementno material movementthe record holds only daily drift and scoring model releases
Basisassumeda published average, not your estate

$7,370 = $4.99M incident cost x 0.42806422275080447 exposure x 0.00345 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.00345EPSSNOT IN KEVas of 2026-09-20
Severity5.1 MEDIUMreceipt
Harmpartial impactreceipt
Exploitationnone in held sources
Defensefix version namedreceipt
Movementrisenreceipt
PLATEAU10Minimal movement since 2024-02-08, 949 days at 0.00, as of 2026-09-14. arc-rules@v1

Foresight · where to check next

Apple iOSAndroidMicrosoft WindowsCisco SmallMicrosoft Windows28807

This record is one instance of CWE-295, improper certificate validation. The index holds 1581 prior instances of this class, 5 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1

Full pattern panel

Prior records in this weakness class. Each is its own record, dated and receipted.
Color is a claim, not decoration:the hostile worldthe defenseno signalspoke length is how much of the record matches, not how bad it is

Sources disagree here.

Severity score
Zscaler5.1 MEDIUMreceipt
NVD7.5 HIGHreceipt
What it costs
ZscalerPartial confidentiality and integrity lossreceipt
NVDComplete integrity lossreceipt

Both shown, dated. We don't pick winners. disagreement-rules@v1

Running Zscaler ZIA? Check your version

A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.

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Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachneeds local access · no privileges required · no user interaction · low attack complexityreceipt
ImpactPartial confidentiality and integrity lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-295 Improper Certificate Validationreceipt
Published consequencesCWE-295: Integrity, Authentication: Bypass Protection Mechanism, Gain Privileges or Assume Identity[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

Fixed in6.2r.290receipt
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Nothing observed in held sources.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published
  • RUNG 3Exploited in the wild · CISA KEV listed
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, the CNA5.1 MEDIUMreceipt
CVSS, NVD7.5 HIGHreceipt
Exploit probability0.00345 · top 72% of all CVEsreceipt
Blast breadth1 product across 1 vendorderived
Assigned byZscalerreceipt
Recorded changes13 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productZscaler ZIAreceipt
Published rangeszscaler secure internet and saas access < 6.2r.290receipt
Fixed in6.2r.290receipt

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

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What it is stated by the CNA

In Zscaler Internet Access (ZIA) a mismatch between Connect Host and Client Hello's Server Name Indication (SNI) enables attackers to evade network security controls by hiding their communications within legitimate traffic. receipt

NVD's analysis a second authority

severity
7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
weakness
CWE-295
affected versions
zscaler secure internet and saas access < 6.2r.290
also scored by
[email protected] 5.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

The CNA scored it 5.1 and NVD 7.5. Both are shown because both were published; we do not pick one.

check it yourself help.zscaler.com help.zscaler.com receipt

Movement the material steps

8 Feb 20240.00043
17 Mar 20250.00098 · scoring model v2025.03.14
15 Jun 20260.00342 · scoring model v2026.06.15
14 Sep 20260.00345
Show all 13 observations
8 Feb 20240.00043
10 Feb 20240.00048
31 Dec 20240.00051
6 Feb 20250.00064
4 Mar 20250.00069
17 Mar 20250.00098
29 Mar 20250.00081
30 Mar 20250.00098
15 Apr 20250.00038
18 Nov 20250.00102
21 Nov 20250.00038
15 Jun 20260.00342
14 Sep 20260.00345

13 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.00345Published2024-01-31Index as of2026-09-14

The record had been public for 2 years, 7 months when this index was last written.

Published 2024-01-31 receipt · Index as of 2026-09-14 derived

The pattern, elsewhere

This record is one instance of CWE-295, improper certificate validation. The index holds 1581 prior instances of this class, 5 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]

CVE-2023-41991 · Apple iOS and iPadOSmatches 5 of 9KEV listed · 2023receipt
CVE-2023-20963 · Androidmatches 4 of 9KEV listed · 2023receipt
CVE-2020-0601 · Microsoft Windowsmatches 4 of 9KEV listed · 2020receipt
CVE-2022-20703 · Cisco Small Business RV Series Router Firmwarematches 3 of 9KEV listed · 2022receipt
CVE-2022-26923 · Microsoft Windows 10 Version 1809matches 3 of 9KEV listed · 2022receipt

"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1

1581 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.

No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.

Siblings and hubs

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These are index-wide views, not findings about CVE-2023-28807.

What usually comes next

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