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Esp IdfApplication · Espressif

CVE-2026-25508

MEDIUM · 6.3 CVSS v3.1 Published 2026-02-04
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
66/100
Remediation priority · Elevated
No privileges Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In versions 5.5.2, 5.4.3, 5.3.4, 5.2.6, and 5.1.6, an out-of-bounds read vulnerability was reported in the BLE ATT Prepare Write handling of the BLE provisioning transport (protocomm_ble). The issue can be triggered by a remote BLE client while the device is in provisioning mode. The transport accumulated prepared-write fragments in a fixed-size buffer but incorrectly tracked the cumulative length. By sending repeated prepare write requests with overlapping offsets, a remote client could cause the reported length to exceed the allocated buffer size. This inflated length was then passed to provisioning handlers during execute-write processing, resulting in an out-of-bounds read and potential memory corruption. This issue has been patched in versions 5.5.3, 5.4.4, 5.3.5, 5.2.7, and 5.1.7.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-125

The code reads past the end (or before the start) of a buffer, returning memory that was never meant to be exposed. Attackers use it to leak secrets like keys or to defeat memory-protection defences. Remediation is validating indices and lengths before every read.

General guidance for the out-of-bounds read class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Esp IdfApplication
Affected:= 5.1.6= 5.2.6= 5.3.4= 5.4.3= 5.5.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix High confidence

ESP-IDF 5.1.7 (for 5.1.x), 5.2.7 (for 5.2.x), 5.3.5 (for 5.3.x), 5.4.4 (for 5.4.x), or 5.5.3+ (for 5.5.x)

  1. 1. Identify the current ESP-IDF version in use by checking the version file or running `idf.py --version`
  2. 2. For ESP-IDF 5.1.x: Upgrade to version 5.1.7 or later
  3. 3. For ESP-IDF 5.2.x: Upgrade to version 5.2.7 or later
  4. 4. For ESP-IDF 5.3.x: Upgrade to version 5.3.5 or later
  5. 5. For ESP-IDF 5.4.x: Upgrade to version 5.4.4 or later
  6. 6. Fetch the new version using the ESP-IDF install script: `./install.sh esp32` (or relevant target)
  7. 7. Set the new environment: `source ./export.sh`
  8. 8. Verify the upgrade by running `idf.py --version` to confirm the patched version is active
Caveat Review project dependencies for compatibility with newer ESP-IDF versions; some components or third-party libraries may require updates

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-25508 in production — separate from our analysis above.

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