CVE-2026-81507

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (18th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-98738 (ENISA EUVD)Source: ENISA EUVD

6.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. Prior to 5.2.8, 5.3.6, 5.5.5, 6.0.3, and 6.1-rc1, ESP-IDF BlueDroid L2CAP configuration-option processing in l2c_main.c and l2c_utils.c does not consistently validate option lengths against the remaining received packet bytes. A remote unauthenticated BR/EDR peer within radio range can send a malformed L2CAP configuration request that causes an out-of-bounds read, and under some runtime conditions limited adjacent Bluetooth stack memory can be included in an outbound L2CAP Configuration Response. The issue affects ESP32-class products using the BlueDroid host stack with Classic Bluetooth enabled. This issue is fixed in 5.2.8, 5.3.6, 5.5.5, 6.0.3, and 6.1-rc1.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
18th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

October 13, 2026

Last Modified

October 16, 2026

Advisory Details (10)

Auto-updated Oct 13, 2026
Patch available. Sources: github, github_commit, github_release.
GitHub release Patch Available

ESP-IDF Release v5.3.6

Patch available: espressif/esp-idf v5.3.6

https://github.com/espressif/esp-idf/releases/tag/v5.3.6
GitHub release Patch Available

ESP-IDF Release v5.2.8

Patch available: espressif/esp-idf v5.2.8

https://github.com/espressif/esp-idf/releases/tag/v5.2.8
GitHub commit

commit c8cd8f4f3019 (espressif/esp-idf)

Fix landed in espressif/esp-idf commit c8cd8f4f3019 — awaiting tagged release

https://github.com/espressif/esp-idf/commit/c8cd8f4f3019ae2f912c8cbe9974445e8d9b8749
GitHub commit

commit c2610255a5ad (espressif/esp-idf)

Fix landed in espressif/esp-idf commit c2610255a5ad — awaiting tagged release

https://github.com/espressif/esp-idf/commit/c2610255a5adce651ca582bb82368c3dd0ee2834
GitHub commit

commit 9a6d04f65e0e (espressif/esp-idf)

Fix landed in espressif/esp-idf commit 9a6d04f65e0e — awaiting tagged release

https://github.com/espressif/esp-idf/commit/9a6d04f65e0e341e7d72bd417c9f31b8a04ce846
GitHub commit

commit 8de265dc44b1 (espressif/esp-idf)

Fix landed in espressif/esp-idf commit 8de265dc44b1 — awaiting tagged release

https://github.com/espressif/esp-idf/commit/8de265dc44b1b22c749ea44ee7c609b3da4162f0
GitHub commit

commit 5731c63ece12 (espressif/esp-idf)

Fix landed in espressif/esp-idf commit 5731c63ece12 — awaiting tagged release

https://github.com/espressif/esp-idf/commit/5731c63ece128f156939b9f734256e2227c1442a
GitHub commit

commit 1e07f6d83ca8 (espressif/esp-idf)

Fix landed in espressif/esp-idf commit 1e07f6d83ca8 — awaiting tagged release

https://github.com/espressif/esp-idf/commit/1e07f6d83ca892630a7210df2958455f7ca77b4a
GitHub commit

commit 14c99559b433 (espressif/esp-idf)

Fix landed in espressif/esp-idf commit 14c99559b433 — awaiting tagged release

https://github.com/espressif/esp-idf/commit/14c99559b4337cabcf0f09c21d16b93c4cd7a6fe
GitHub advisoryMentions a patch (unverified)

Bluetooth Classic L2CAP Heap Memory Disclosure Allowing Unauthorized Access to Sensitive Data · Advisory · espressif/esp-idf · GitHub

https://github.com/espressif/esp-idf/security/advisories/GHSA-v335-fxwc-rc44

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 29× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  2. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  3. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  4. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  5. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  6. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  7. 2026-10-28 02:25 UTCOSV refresh
  8. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  9. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  10. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  11. 2026-10-25 13:58 UTCEG score recompute
  12. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  13. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  14. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  15. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  16. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  17. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  18. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  19. 2026-10-18 03:09 UTCEG score recompute
  20. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  21. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  22. 2026-10-16 16:14 UTCEG score recompute
  23. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  24. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  25. 2026-10-14 15:34 UTCEG score recompute
Show 4 more
  1. 2026-10-14 15:06 UTCEG score recompute
  2. 2026-10-13 16:29 UTCEG score recompute
  3. 2026-10-13 15:21 UTCEG score recomputeFirst assessed: 6.5 MEDIUM
  4. 2026-10-13 15:19 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-81507?
CVE-2026-81507 is a medium-severity vulnerability; its CVE record was published on October 13, 2026. ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. Prior to 5.2.8, 5.3.6, 5.5.5, 6.0.3, and 6.1-rc1, ESP-IDF BlueDroid L2CAP configuration-option processing in l2c_main.c and l2c_utils.c does not consistently validate option lengths against the remaining received packet bytes.…
When was the CVE record for CVE-2026-81507 published?
The CVE record for CVE-2026-81507 was published on October 13, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 16, 2026; the record at its source may have been updated since.
Is CVE-2026-81507 actively exploited?
CVE-2026-81507 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (18th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-81507?
CVE-2026-81507 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-81507?
A fix for CVE-2026-81507 is available: update to the fixed version the vendor names in its advisory.

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