vciy

CVE-2025-52496

INDEX BUILT · 2026-09-20

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Mbed TLS before 3.6.4 has a race condition in AESNI detection if certain compiler optimizations occur

CVE-2025-524964 of 4 sources documented this
22

rank 22 = 0 + 20 + 0 + 2 + 0

rank@v1 · backlog

Someone is already using it

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

EPSS 0.00188  ·  without this subject the record ranks 22

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 7.8, 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 22

How much of the world it touches

NVD CPE configurations

1 product in the CPE ranges  ·  without this subject the record ranks 20

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 22

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$8,270over 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

$8,270 = $4.99M incident cost x 0.8814887365328109 exposure x 0.00188 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

0.00188EPSSNOT IN KEVas of 2026-09-20
Severity7.8 HIGHreceipt
Harmpartial impactreceipt
Exploitationnone in held sources
Defensefix version namedreceipt
Movementrisenreceipt
PLATEAU10Minimal movement since 2025-07-05, 438 days at 0.00, as of 2026-09-16. arc-rules@v1

Foresight · where to check next

No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.

Color is a claim, not decoration:the hostile worldthe defenseno signal

Running Mbed mbedtls? Check your version

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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 · high attack complexityreceipt
ImpactComplete confidentiality and integrity loss, with impact beyond the vulnerable componentreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-733 Compiler Optimization Removal or Modification of Security-critical Codereceipt
Published consequencesCWE-733: Access Control, Other: Bypass Protection Mechanism, Alter Execution Logic[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

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

Fixed in3.6.4receipt
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 CNA7.8 HIGHreceipt
CVSS, NVD7.8 HIGHreceipt
Exploit probability0.00188 · top 91% of all CVEsreceipt
Blast breadth1 product across 1 vendorderived
Assigned bymitrereceipt
Recorded changes18 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productMbed mbedtlsreceipt
Published rangesarm mbed tls < 3.6.4receipt
Fixed in3.6.4receipt

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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Attack path

Local accessno credentials, no interactionMbed mbedtlsCWE-733 weaknessAdjacent componentsscope changeConfidentiality and integrity lossC:H / I:Hexploits CWE-733scope changedata compromise

What it is stated by the CNA

Mbed TLS before 3.6.4 has a race condition in AESNI detection if certain compiler optimizations occur. An attacker may be able to extract an AES key from a multithreaded program, or perform a GCM forgery. receipt

NVD's analysis a second authority

severity
7.8 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
weakness
CWE-733
affected versions
arm mbed tls < 3.6.4
also scored by
[email protected] 7.8 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

check it yourself github.com receipt

Movement the material steps

5 Jul 20250.00013
15 Jun 20260.00189 · scoring model v2026.06.15
16 Sep 20260.00188
Show all 18 observations
5 Jul 20250.00013
10 Jul 20250.00016
5 Aug 20250.00018
10 Sep 20250.00019
16 Sep 20250.00018
23 Sep 20250.00023
3 Nov 20250.00029
30 Nov 20250.00015
12 Dec 20250.00017
28 Jan 20260.0002
9 Mar 20260.00021
20 Mar 20260.00029
30 Mar 20260.00032
16 Apr 20260.00038
30 Apr 20260.00102
19 May 20260.00085
15 Jun 20260.00189
16 Sep 20260.00188

18 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 0.00188Published2025-07-04Index as of2026-09-16

The record had been public for 1 year, 2 months when this index was last written.

Published 2025-07-04 receipt · Index as of 2026-09-16 derived

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