vciy

CVE-2025-49600

INDEX BUILT · 2026-09-20

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In MbedTLS 3.3.0 before 3.6.4, mbedtls_lms_verify may accept invalid signatures if hash computation fails and internal errors go unchecked, enabling…

CVE-2025-496004 of 4 sources documented this
14

rank 14 = 0 + 12 + 0 + 2 + 0

rank@v1 · backlog

Someone is already using it

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

EPSS 0.00132  ·  without this subject the record ranks 14

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 4.9, from the CNA  ·  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 14

How much of the world it touches

NVD CPE configurations

1 product in the CPE ranges  ·  without this subject the record ranks 12

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 14

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$4,030over 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

$4,030 = $4.99M incident cost x 0.6121449559255632 exposure x 0.00132 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

0.00132EPSSNOT IN KEVas of 2026-09-20
Severity4.9 MEDIUMreceipt
Harmpartial impactreceipt
Exploitationnone in held sources
Defensefix version namedreceipt
Movementrisenreceipt
PLATEAU10Minimal movement since 2025-07-05, 419 days at 0.00, as of 2026-08-28. 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

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Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachneeds physical access · no privileges required · no user interaction · high attack complexityreceipt
ImpactComplete integrity loss, with impact beyond the vulnerable componentreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-325 Missing Cryptographic Stepreceipt
Published consequencesCWE-325: Access Control: Bypass Protection Mechanism; Confidentiality, Integrity: Read Application Data, Modify Application Data; Accountability, Non-Repudiation: Hide Activities[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 CNA4.9 MEDIUMreceipt
Exploit probability0.00132 · top 97% of all CVEsreceipt
Blast breadth1 product across 1 vendorderived
Assigned bymitrereceipt
Recorded changes17 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productMbed mbedtlsreceipt
Published rangestrustedfirmware mbed tls >= 3.3.0 < 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

Physical accessno credentials, no interactionMbed mbedtlsCWE-325 weaknessAdjacent componentsscope changeIntegrity lossI:Hexploits CWE-325scope changedata compromise

What it is stated by the CNA

In MbedTLS 3.3.0 before 3.6.4, mbedtls_lms_verify may accept invalid signatures if hash computation fails and internal errors go unchecked, enabling LMS (Leighton-Micali Signature) forgery in a fault scenario. Specifically, unchecked return values in mbedtls_lms_verify allow an attacker (who can induce a hardware hash accelerator fault) to bypass LMS signature verification by reusing stale stack data, resulting in acceptance of an invalid signature. In mbedtls_lms_verify, the return values of the internal Merkle tree functions create_merkle_leaf_value and create_merkle_internal_value are not checked. These functions return an integer that indicates whether the call succeeded or not. receipt

Read the rest of the CNA's description

If a failure occurs, the output buffer (Tc_candidate_root_node) may remain uninitialized, and the result of the signature verification is unpredictable. When the software implementation of SHA-256 is used, these functions will not fail. However, with hardware-accelerated hashing, an attacker could use fault injection against the accelerator to bypass verification.

NVD's analysis a second authority

weakness
CWE-325
affected versions
trustedfirmware mbed tls >= 3.3.0 < 3.6.4
also scored by
[email protected] 4.9 CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N

check it yourself github.com receipt

Movement the material steps

5 Jul 20250.00014
15 Jun 20260.00129 · scoring model v2026.06.15
28 Aug 20260.00132
Show all 17 observations
5 Jul 20250.00014
10 Jul 20250.00011
18 Jul 20258e-05
5 Aug 20259e-05
3 Nov 20250.00011
30 Nov 20257e-05
12 Dec 20258e-05
28 Jan 20269e-05
7 Feb 20268e-05
9 Mar 20269e-05
20 Mar 20260.00012
30 Mar 20260.00014
30 Apr 20260.00046
15 Jun 20260.00129
23 Jun 20260.00125
30 Jul 20260.00126
28 Aug 20260.00132

17 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 0.00132Published2025-07-04Index as of2026-08-28

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

Published 2025-07-04 receipt · Index as of 2026-08-28 derived

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