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.
CVE-2026-81507
MEDIUMPre-NVD 6.56.5
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). No GitHub Security Advisory CVSS is on record for this CVE.
Triggered by: Headline CVSS from a secondary CVSS source
Sources: a secondary CVSS source
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: —CVSS: 6.5Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 6.5
- EG Score
- 6.5MEDIUMlow confidence
- EG Risk
- 29EG Risk 29/100
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computed (value × EchelonGraph’s weight)Severity65% × 45%The EG Score, 6.5 of 10.Exploitation0% × 40%No KEV listing, EG-KEV tier or EPSS when EchelonGraph scored this CVE.Automatability0% × 15%CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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
- —
- EPSS %ILE
- —
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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 13, 2026
Advisory Details (10)
Auto-updated Oct 13, 2026Patch 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/v5.3.6GitHub 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/v5.2.8GitHub commit
commit c8cd8f4f3019 (espressif/esp-idf)
Fix landed in espressif/esp-idf commit c8cd8f4f3019 — awaiting tagged release
https://github.com/espressif/esp-idf/commit/c8cd8f4f3019ae2f912c8cbe9974445e8d9b8749GitHub commit
commit c2610255a5ad (espressif/esp-idf)
Fix landed in espressif/esp-idf commit c2610255a5ad — awaiting tagged release
https://github.com/espressif/esp-idf/commit/c2610255a5adce651ca582bb82368c3dd0ee2834GitHub commit
commit 9a6d04f65e0e (espressif/esp-idf)
Fix landed in espressif/esp-idf commit 9a6d04f65e0e — awaiting tagged release
https://github.com/espressif/esp-idf/commit/9a6d04f65e0e341e7d72bd417c9f31b8a04ce846GitHub commit
commit 8de265dc44b1 (espressif/esp-idf)
Fix landed in espressif/esp-idf commit 8de265dc44b1 — awaiting tagged release
https://github.com/espressif/esp-idf/commit/8de265dc44b1b22c749ea44ee7c609b3da4162f0GitHub commit
commit 5731c63ece12 (espressif/esp-idf)
Fix landed in espressif/esp-idf commit 5731c63ece12 — awaiting tagged release
https://github.com/espressif/esp-idf/commit/5731c63ece128f156939b9f734256e2227c1442aGitHub commit
commit 1e07f6d83ca8 (espressif/esp-idf)
Fix landed in espressif/esp-idf commit 1e07f6d83ca8 — awaiting tagged release
https://github.com/espressif/esp-idf/commit/1e07f6d83ca892630a7210df2958455f7ca77b4aGitHub commit
commit 14c99559b433 (espressif/esp-idf)
Fix landed in espressif/esp-idf commit 14c99559b433 — awaiting tagged release
https://github.com/espressif/esp-idf/commit/14c99559b4337cabcf0f09c21d16b93c4cd7a6feGitHub 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-rc44Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× 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.
- 2026-10-13 16:29 UTCEG score recompute
- 2026-10-13 15:21 UTCEG score recomputeFirst assessed: 6.5 MEDIUM
- 2026-10-13 15:19 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
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 l2cmain.c and l2cutils.c does not consistently validate option lengths against the remaining received packet bytes. A…
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 13, 2026; the record at its source may have been updated since.
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). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
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.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-81507
Is Your Infrastructure Affected by CVE-2026-81507?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.