CVE-2026-55490

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: 0.7% (52nd 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
Elevated

Also known asEUVD-2026-42110 (ENISA EUVD)Source: ENISA EUVD

6.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 6.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

OpenWrt is a Linux operating system targeting embedded devices. Before v25.12.5, an integer underflow in handle_send_a() of the Emergency Access Daemon allows any unauthenticated attacker on the local network to crash the daemon by sending a single crafted UDP packet. The message length underflows before a bounds check and is then passed to memcpy as a very large size. This issue is fixed v25.12.5.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
45
EG Risk 45/100

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.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (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
0.7%
EPSS %ILE
52nd
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
0.7% 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; Track* at high (mission-essential systems).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 low or medium mission impact; Track* at high (mission-essential systems).

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

Exploitation public PoC (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

July 7, 2026

Last Modified

July 10, 2026

Advisory Details (3)

Auto-updated Jul 7, 2026
Patch available. Sources: github_commit, github_release, github.
GitHub advisoryMentions a patch (unverified)

EAD Integer Underflow → Pre-Auth Denial of Service · Advisory · openwrt/openwrt · GitHub

https://github.com/openwrt/openwrt/security/advisories/GHSA-9558-77jp-g3fw
GitHub release Patch Available

v25.12.5

Patch available: openwrt/openwrt v25.12.5

https://github.com/openwrt/openwrt/releases/tag/v25.12.5
GitHub commit

commit 63c0767f3d02 (openwrt/openwrt)

Fix landed in openwrt/openwrt commit 63c0767f3d02 — awaiting tagged release

https://github.com/openwrt/openwrt/commit/63c0767f3d02f7b10b0f0b5293366bd059a08ca5

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 39× 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.

Showing the most recent 100 of 159 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 59 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  2. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  3. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  4. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  5. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  6. 2026-10-30 10:55 UTCOSV refresh
  7. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  8. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  9. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  10. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  11. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  12. 2026-10-25 14:18 UTCEG score recompute
  13. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  14. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  15. 2026-10-22 21:15 UTCEG score recompute
  16. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  17. 2026-10-21 20:25 UTCOSV refresh
  18. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  19. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  20. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  21. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  22. 2026-10-18 03:30 UTCEG score recompute
  23. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  24. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  25. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
Show 75 more
  1. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  2. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  3. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  4. 2026-10-12 15:55 UTCEG score recompute
  5. 2026-10-11 19:39 UTCEG score recompute
  6. 2026-10-11 16:54 UTCEG score recompute
  7. 2026-10-11 14:17 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  11. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  13. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  14. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  15. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  16. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  17. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  18. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  20. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  22. 2026-09-28 13:35 UTCEG score recompute
  23. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  24. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  25. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  26. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  27. 2026-09-23 06:16 UTCEG score recompute
  28. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  29. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  30. 2026-09-18 05:48 UTCEG score recompute
  31. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  32. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  33. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  34. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  35. 2026-09-14 11:19 UTCEG score recompute
  36. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  37. 2026-09-13 08:29 UTCEG score recompute
  38. 2026-09-12 03:41 UTCEG score recompute
  39. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  40. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  41. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  42. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  43. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  44. 2026-09-05 22:53 UTCEG score recompute
  45. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  46. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  47. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  48. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  49. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  50. 2026-08-30 07:42 UTCEG score recompute
  51. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  52. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  53. 2026-08-28 04:30 UTCEG score recompute
  54. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  55. 2026-08-27 01:52 UTCEG score recompute
  56. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  57. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  58. 2026-08-25 13:31 UTCEG score recompute
  59. 2026-08-24 10:57 UTCEG score recompute
  60. 2026-08-23 08:47 UTCEG score recompute
  61. 2026-08-23 00:19 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  62. 2026-08-22 06:32 UTCEG score recompute
  63. 2026-08-21 23:49 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  64. 2026-08-21 04:22 UTCEG score recompute
  65. 2026-08-20 22:55 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  66. 2026-08-20 02:10 UTCEG score recompute
  67. 2026-08-19 17:04 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  68. 2026-08-18 20:47 UTCEG score recompute
  69. 2026-08-18 13:48 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  70. 2026-08-17 13:47 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  71. 2026-08-17 12:15 UTCEG score recompute
  72. 2026-08-16 14:56 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  73. 2026-08-16 09:58 UTCEG score recompute
  74. 2026-08-16 02:14 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  75. 2026-08-15 07:49 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-55490?
CVE-2026-55490 is a medium-severity vulnerability; its CVE record was published on July 7, 2026. OpenWrt is a Linux operating system targeting embedded devices. Before v25.12.5, an integer underflow in handle_send_a() of the Emergency Access Daemon allows any unauthenticated attacker on the local network to crash the daemon by sending a single crafted UDP packet. The message length underflows…
When was the CVE record for CVE-2026-55490 published?
The CVE record for CVE-2026-55490 was published on July 7, 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 July 10, 2026; the record at its source may have been updated since.
Is CVE-2026-55490 actively exploited?
CVE-2026-55490 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (52nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55490?
CVE-2026-55490 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-2026-55490?
A fix for CVE-2026-55490 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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