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NVD / CVE Program· CNA mitre

CVE-2025-59438: Mbed TLS through 3.6.4 has an Observable Timing Discrepancy.

Noroxi assessment

Priority: Monitor (action score 21/100)

  • 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: 0.26% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: mbedtls (Alpine:v3.20) 3.6.5-r0; mbedtls (Debian:13) 3.6.5-0.1~deb13u1; mbedtls (Debian:14) 3.6.5-0.1.

Low priority for now. Upgrade to mbedtls (Alpine:v3.20) 3.6.5-r0; mbedtls (Debian:13) 3.6.5-0.1~deb13u1; mbedtls (Debian:14) 3.6.5-0.1 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

MediumCVSS 5.3 · v3.1—No exploit Fix available
Published
Oct 21, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 18th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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-2025-59438

When you'll hear from us

  • when it enters CISA KEV
  • 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
armmbed tls

Check your server's TLS configuration

The Mbed TLS version can't be seen from outside; the free SSL checker tests your certificate, enabled TLS versions and weak ciphers. Confirm the version on your server with the package manager.

Run the SSL check

Affected versions

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

  • arm mbed tlsbefore 3.6.5

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.20mbedtlsbefore 3.6.5-r03.6.5-r0
Debian:12mbedtlsfrom 0—
Debian:13mbedtlsbefore 3.6.5-0.1~deb13u13.6.5-0.1~deb13u1
Debian:14mbedtlsbefore 3.6.5-0.13.6.5-0.1
openSUSE:Leap 16.0mbedtlsbefore 3.6.6-bp160.1.13.6.6-bp160.1.1
openSUSE:Leap 16.0mbedtls-2before 2.28.10-bp160.2.12.28.10-bp160.2.1
openSUSE:Leap 16.0micropythonbefore 1.26.0-bp160.1.11.26.0-bp160.1.1
openSUSE:Leap 16.0ovmfbefore 202502-160000.4.1202502-160000.4.1
openSUSE:Tumbleweedmbedtlsbefore 3.6.5-1.13.6.5-1.1
openSUSE:Tumbleweedmbedtls-2before 2.28.10-5.12.28.10-5.1
openSUSE:Tumbleweedmicropythonbefore 1.26.0-2.11.26.0-2.1
openSUSE:Tumbleweedovmfbefore 202602-5.1202602-5.1
openSUSE:Tumbleweedvlangbefore 0.5-2.10.5-2.1
SUSE:Linux Enterprise Module for Package Hub 15 SP7ovmfbefore 202408-150700.3.15.1202408-150700.3.15.1
SUSE:Linux Micro 6.1ovmfbefore 202402-slfo.1.1_2.1202402-slfo.1.1_2.1
SUSE:Linux Micro 6.2ovmfbefore 202502-160000.4.1202502-160000.4.1

Same product

arm: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-47917Mbed TLS before 3.6.4 allows a use-after-free in certain situations of applications that are developed in accordance with the documentation.
    40Plan
  • CVE-2021-44732Mbed TLS before 3.0.1 has a double free in certain out-of-memory conditions, as demonstrated by an mbedtls_ssl_set_session() failure.
    40Plan
  • CVE-2017-18187In ARM mbed TLS before 2.7.0, there is a bounds-check bypass through an integer overflow in PSK identity parsing in the ssl_parse_client_psk
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-48965Jul 20, 2025 · Mbed TLS before 3.6.4 has a NULL pointer dereference because mbedtls_asn1_store_named_data can trigger conflicting data with val.p of NULL b
    30Monitor
  • ← EarlierCVE-2025-54764Oct 20, 2025 · Mbed TLS before 3.6.5 allows a local timing attack against certain RSA operations, and direct calls to mbedtls_mpi_mod_inv or mbedtls_mpi_gc
    24Monitor
  • Later →CVE-2026-25835Apr 1, 2026 · Mbed TLS before 3.6.6 and TF-PSA-Crypto before 1.1.0 misuse seeds in a Pseudo-Random Number Generator (PRNG).
    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
alpine:mbedtls3.6.5-r0 · Alpine:v3.20Package registry (OSV)
debian:mbedtls3.6.5-0.1~deb13u1 · Debian:13Package registry (OSV)
opensuse:mbedtls3.6.5-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:mbedtls-22.28.10-5.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:micropython1.26.0-2.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:ovmf202602-5.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:vlang0.5-2.1 · openSUSE:TumbleweedPackage registry (OSV)
suse:ovmf202408-150700.3.15.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7Package 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.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

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

  • CVE-2025-547641 days apartMbed TLS before 3.6.5 allows a local timing attack against certain RSA operations, and direct calls to mbedtls_mpi_mod_inv or mbedtls_mpi_gc
    24Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-208 · Observable Timing Discrepancy

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records