ESPAsyncWebServer is an asynchronous HTTP and WebSocket server library for ESP32, ESP8266, RP2040 and RP2350. Prior to version 3.11.2, the multipart parser in src/WebRequest.cpp frees _itemBuffer and sets it to NULL when BOUNDARY_OR_DATA matches the closing boundary of a file part, before confirming the following terminator, while leaving _itemIsFile true. If the next byte is neither the final closing dashes nor a clean CRLF, the DASH3_OR_RETURN2 or EXPECT_FEED2 rewind branch re-injects provisionally consumed bytes through itemWriteByte. Because _itemIsFile remains true, _itemBuffer[_itemBufferIndex++] writes through a null pointer. On ESP32 this causes a StoreProhibited exception, panic and device reboot, producing remote denial of service. A route with a non-trivial body/upload handler, such as a file-upload or web-OTA endpoint, must be present. This issue is fixed in version 3.11.2.
CVE-2026-62966
“—” beside the score: it is equal to the CVSS score beside it.
This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (37th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-114469 (ENISA EUVD)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHmedium confidence
- EG Risk
- 49EG Risk 49/100
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)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.4% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.4%
- EPSS %ILE
- 37th
- 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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-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
- 0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-06). 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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 30, 2026
Last Modified
November 6, 2026
Advisory Details (3)
Auto-updated Oct 30, 2026GitHub - ESP32Async/ESPAsyncWebServer at v3.11.2 · GitHub
https://github.com/ESP32Async/ESPAsyncWebServer/tree/v3.11.2commit 4efbd35e597d (ESP32Async/ESPAsyncWebServer)
Patch available: ESP32Async/ESPAsyncWebServer v3.11.2 (contains commit 4efbd35e597d)
https://github.com/ESP32Async/ESPAsyncWebServer/commit/4efbd35e597d91f01749f2d4a14bb78fba8ea02eNull-pointer write in ESPAsyncWebServer multipart parser · Advisory · ESP32Async/ESPAsyncWebServer · GitHub
https://github.com/ESP32Async/ESPAsyncWebServer/security/advisories/GHSA-8m8p-vhxc-jmjwWeakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 16× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.
- 2026-11-13 16:53 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-06 19:27 UTCEchelonGraph re-scored
- 2026-11-06 18:27 UTCEchelonGraph re-scored
- 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.4% · 36th percentile
- 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.4% · 36th percentile
- 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 36th percentile
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 36th percentile
- 2026-10-30 22:02 UTCENISA EUVD ID recordedEUVD-2026-114469 · Source: ENISA EUVD
- 2026-10-30 21:26 UTCEchelonGraph re-scored
- 2026-10-30 20:59 UTCEchelonGraph re-scoredFirst assessed: 7.5 HIGH
- 2026-10-30 20:58 UTCMITRE cvelistV5first tracked
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Frequently asked(5)
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Dependency Blast Radius
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