CVE-2026-55490

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7%, top 50% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 6.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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
6.5(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

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
Severity65% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
50%
KEV
Not listed

Published

July 7, 2026

Last Modified

July 10, 2026

Advisory Details (3)

Auto-updated Jul 7, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

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 6× in last 7d / 41× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-08 22:01 UTCEPSS rescore
  4. 2026-09-07 16:01 UTCEPSS rescore
  5. 2026-09-06 13:47 UTCEPSS rescore
  6. 2026-09-05 22:53 UTCEG score recompute
  7. 2026-09-04 05:06 UTCEPSS rescore
  8. 2026-09-02 14:12 UTCEPSS rescore
  9. 2026-09-01 13:54 UTCEPSS rescore
  10. 2026-09-01 04:40 UTCEPSS rescore
  11. 2026-08-30 19:17 UTCEPSS rescore
  12. 2026-08-30 07:42 UTCEG score recompute
  13. 2026-08-30 01:22 UTCEPSS rescore
  14. 2026-08-28 21:41 UTCEPSS rescore
  15. 2026-08-28 04:30 UTCEG score recompute
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-27 01:52 UTCEG score recompute
  18. 2026-08-26 14:46 UTCEPSS rescore
  19. 2026-08-25 13:49 UTCEPSS rescore
  20. 2026-08-25 13:31 UTCEG score recompute
  21. 2026-08-24 10:57 UTCEG score recompute
  22. 2026-08-23 08:47 UTCEG score recompute
  23. 2026-08-23 00:19 UTCEPSS rescore
  24. 2026-08-22 06:32 UTCEG score recompute
  25. 2026-08-21 23:49 UTCEPSS rescore
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  1. 2026-08-21 04:22 UTCEG score recompute
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-20 02:10 UTCEG score recompute
  4. 2026-08-19 17:04 UTCEPSS rescore
  5. 2026-08-18 20:47 UTCEG score recompute
  6. 2026-08-18 13:48 UTCEPSS rescore
  7. 2026-08-17 13:47 UTCEPSS rescore
  8. 2026-08-17 12:15 UTCEG score recompute
  9. 2026-08-16 14:56 UTCEPSS rescore
  10. 2026-08-16 09:58 UTCEG score recompute
  11. 2026-08-16 02:14 UTCEPSS rescore
  12. 2026-08-15 07:49 UTCEG score recompute
  13. 2026-08-15 01:30 UTCEPSS rescore
  14. 2026-08-14 04:09 UTCEG score recompute
  15. 2026-08-13 22:00 UTCEPSS rescore
  16. 2026-08-13 02:00 UTCEG score recompute
  17. 2026-08-12 13:51 UTCEPSS rescore
  18. 2026-08-11 23:50 UTCEG score recompute
  19. 2026-08-11 00:00 UTCEPSS rescore
  20. 2026-08-09 19:30 UTCEG score recompute
  21. 2026-08-09 13:46 UTCEPSS rescore
  22. 2026-08-08 17:21 UTCEG score recompute
  23. 2026-08-08 16:37 UTCEPSS rescore
  24. 2026-08-07 15:11 UTCEG score recompute
  25. 2026-08-06 13:47 UTCEPSS rescore
  26. 2026-08-06 13:01 UTCEG score recompute
  27. 2026-08-05 19:17 UTCEPSS rescore
  28. 2026-08-05 10:52 UTCEG score recompute
  29. 2026-08-04 15:10 UTCEPSS rescore
  30. 2026-08-04 10:39 UTCEPSS rescore
  31. 2026-08-04 08:39 UTCEG score recompute
  32. 2026-08-03 10:36 UTCEPSS rescore
  33. 2026-08-02 04:03 UTCEG score recompute
  34. 2026-08-02 02:27 UTCEPSS rescore
  35. 2026-08-01 04:16 UTCEPSS rescore
  36. 2026-07-30 23:30 UTCEG score recompute
  37. 2026-07-30 16:28 UTCEPSS rescore
  38. 2026-07-30 01:30 UTCEPSS rescore
  39. 2026-07-28 17:54 UTCEG score recompute
  40. 2026-07-28 15:37 UTCEPSS rescore
  41. 2026-07-27 15:42 UTCEG score recompute
  42. 2026-07-26 14:54 UTCEPSS rescore
  43. 2026-07-26 12:34 UTCEG score recompute
  44. 2026-07-25 14:18 UTCEPSS rescore
  45. 2026-07-24 14:18 UTCEPSS rescore
  46. 2026-07-23 14:18 UTCEPSS rescore
  47. 2026-07-23 03:20 UTCEG score recompute
  48. 2026-07-22 14:08 UTCEPSS rescore
  49. 2026-07-21 15:25 UTCEPSS rescore
  50. 2026-07-20 17:08 UTCEPSS rescore
  51. 2026-07-19 14:31 UTCEPSS rescore
  52. 2026-07-19 14:31 UTCEPSS rescore
  53. 2026-07-19 02:29 UTCEPSS rescore
  54. 2026-07-18 10:04 UTCEPSS rescore
  55. 2026-07-16 17:03 UTCEPSS rescore
  56. 2026-07-15 16:57 UTCEPSS rescore
  57. 2026-07-15 16:57 UTCEPSS rescore
  58. 2026-07-15 02:00 UTCEPSS rescore
  59. 2026-07-15 02:00 UTCEPSS rescore
  60. 2026-07-13 22:31 UTCEPSS rescore
  61. 2026-07-13 06:13 UTCEPSS rescore
  62. 2026-07-13 06:13 UTCEPSS rescore
  63. 2026-07-12 05:46 UTCEPSS rescore
  64. 2026-07-11 08:27 UTCEPSS rescore
  65. 2026-07-11 08:27 UTCEPSS rescore
  66. 2026-07-09 19:10 UTCEPSS rescore
  67. 2026-07-09 19:10 UTCEPSS rescore
  68. 2026-07-08 15:16 UTCEPSS rescore
  69. 2026-07-08 15:16 UTCEPSS rescore
  70. 2026-07-07 21:37 UTCEG score recompute
  71. 2026-07-07 21:37 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-55490?
CVE-2026-55490 is a medium vulnerability published on July 7, 2026. OpenWrt is a Linux operating system targeting embedded devices. Before v25.12.5, an integer underflow in handlesenda() 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 CVE-2026-55490 disclosed?
CVE-2026-55490 was first published in the National Vulnerability Database on July 7, 2026, with the most recent update on July 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55490 actively exploited?
CVE-2026-55490 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 49.6% of all scored CVEs.
What is the CVSS score of CVE-2026-55490?
CVE-2026-55490 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-55490?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55490, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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