CVE-2026-48490

MEDIUMPre-NVD 6.96.9
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7% (51st 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-2026-76769 (ENISA EUVD)Source: ENISA EUVD

6.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 6.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

ArduinoCore-avr contains the source code and configuration files of the Arduino AVR Boards platform. A vulnerability in versions prior to 1.8.8 allows an attacker to trigger a stack-based buffer overflow when concatenating floating-point values of sufficiently large magnitude onto an Arduino String object. By passing values near the extremes of the float or double range to String::concat(float), String::concat(double), String::operator+=(), or the + operator with a float/double operand, dtostrf() writes beyond the fixed-size stack buffer, causing memory corruption and denial of service. Under specific conditions, this could enable arbitrary code execution on AVR-based Arduino boards. The fix is included starting from the 1.8.8 release.

CVSS v3
6.9
EG Score
6.9MEDIUMmedium confidence
EG Risk
46
EG Risk 46/100

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)
Severity69% × 45%
Impact severity (EG Severity): CVSS 6.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.7% × 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
0.7%
EPSS %ILE
51st
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 (6.9): severity, escalated by confirmed exploitation. This CVE's 6.9 is its impact severity (EG Severity), not escalated.

EG Severity
6.9 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
0.7% 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 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

September 11, 2026

Last Modified

September 30, 2026

Advisory Details (3)

Auto-updated Sep 11, 2026
Patch available. Sources: github_pr, github_release, github.
GitHub release Patch Available

1.8.8

Patch available: arduino/ArduinoCore-avr 1.8.8

https://github.com/arduino/ArduinoCore-avr/releases/tag/1.8.8
GitHub pull request Patch Available

String::concat increase buffer size to fit float/double value

Patch available: arduino/ArduinoCore-avr 1.8.8 (PR #622 merged 2026-05-21)

https://github.com/arduino/ArduinoCore-avr/pull/622/changes/9492e146880d2b05d9cb9191f1bfb2c872a48404
GitHub advisoryMentions a patch (unverified)

ArduinoCore-AVR: Stack-Based Buffer Overflow in String float/double concatenation handler · Advisory · arduino/ArduinoCore-avr · GitHub

https://github.com/arduino/ArduinoCore-avr/security/advisories/GHSA-fhp2-f8hw-mgpj

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 46× 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. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  2. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  3. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  4. 2026-10-30 13:55 UTCOSV refresh
  5. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  6. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  7. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  8. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  9. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  10. 2026-10-25 14:23 UTCEG score recompute
  11. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  12. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  13. 2026-10-22 23:05 UTCEG score recompute
  14. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  15. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  16. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  17. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  18. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  19. 2026-10-18 03:34 UTCEG score recompute
  20. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  21. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  22. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  23. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  24. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  25. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 50th percentile
Show 57 more
  1. 2026-10-12 16:00 UTCEG score recompute
  2. 2026-10-11 19:44 UTCEG score recompute
  3. 2026-10-11 16:58 UTCEG score recompute
  4. 2026-10-11 14:22 UTCEG score recompute
  5. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  6. 2026-10-11 09:45 UTCEG score recompute
  7. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  8. 2026-10-10 07:49 UTCEG score recompute
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  10. 2026-10-09 06:21 UTCEG score recompute
  11. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  12. 2026-10-08 05:04 UTCEG score recompute
  13. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  14. 2026-10-07 03:48 UTCEG score recompute
  15. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  16. 2026-10-06 02:31 UTCEG score recompute
  17. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  18. 2026-10-05 01:14 UTCEG score recompute
  19. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  20. 2026-10-03 23:58 UTCEG score recompute
  21. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  22. 2026-10-02 22:39 UTCEG score recompute
  23. 2026-10-01 21:20 UTCEG score recompute
  24. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  25. 2026-09-30 17:16 UTCEG score recompute
  26. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  27. 2026-09-29 14:19 UTCEG score recompute
  28. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  29. 2026-09-28 13:03 UTCEG score recompute
  30. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  31. 2026-09-27 11:46 UTCEG score recompute
  32. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  33. 2026-09-26 10:10 UTCEG score recompute
  34. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  35. 2026-09-25 08:48 UTCEG score recompute
  36. 2026-09-24 07:32 UTCEG score recompute
  37. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  38. 2026-09-23 06:15 UTCEG score recompute
  39. 2026-09-22 04:58 UTCEG score recompute
  40. 2026-09-21 03:42 UTCEG score recompute
  41. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  42. 2026-09-20 02:25 UTCEG score recompute
  43. 2026-09-19 01:08 UTCEG score recompute
  44. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  45. 2026-09-17 23:52 UTCEG score recompute
  46. 2026-09-16 22:21 UTCEG score recompute
  47. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  48. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  49. 2026-09-15 20:48 UTCEG score recompute
  50. 2026-09-14 19:22 UTCEG score recompute
  51. 2026-09-14 18:28 UTCEG score recompute
  52. 2026-09-13 23:54 UTCEG score recompute
  53. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  54. 2026-09-12 22:38 UTCEG score recompute
  55. 2026-09-11 21:21 UTCEG score recompute
  56. 2026-09-11 21:14 UTCEG score recomputeFirst assessed: 6.9 MEDIUM
  57. 2026-09-11 21:13 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-48490?
CVE-2026-48490 is a medium-severity vulnerability; its CVE record was published on September 11, 2026. ArduinoCore-avr contains the source code and configuration files of the Arduino AVR Boards platform. A vulnerability in versions prior to 1.8.8 allows an attacker to trigger a stack-based buffer overflow when concatenating floating-point values of sufficiently large magnitude onto an Arduino String…
When was the CVE record for CVE-2026-48490 published?
The CVE record for CVE-2026-48490 was published on September 11, 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 September 30, 2026; the record at its source may have been updated since.
Is CVE-2026-48490 actively exploited?
CVE-2026-48490 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (51st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-48490?
CVE-2026-48490 has a CVSS base score of 6.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-48490?
A fix for CVE-2026-48490 is available: update to the fixed version the vendor names in its advisory.

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