CVE-2026-56786

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-06-25. The CNA's CVSS baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: the CNA's CVSS, EPSS, GitHub Security Advisory
Elevated

Also known asEUVD-2026-39528 (ENISA EUVD) · GHSA-5cx9-6hw2-hchv (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan mitigationNo fix is confirmed yet: check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high (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: 9.8Exploit: No code on recordExposed services: Not assessed

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

The CVE record's CNA (VulnCheck) lists tomojitakasu RTKLIB versions up to and including 2.4.3 as affected. No release containing a fix is confirmed on record.

RTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in decode_type1033 function that fails to clamp length counters to destination buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor fields. An attacker controlling an NTRIP or serial RTCM3 correction stream can craft a valid CRC-bearing type-1033 message to corrupt adjacent rtcm_t object members, potentially achieving arbitrary code execution or denial of service.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
75
EG Risk 75/100

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)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 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.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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: No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.
EPSS PROB
0.7%
EPSS %ILE
54th
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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.7% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.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, Track* at medium and Attend at high mission impact.

No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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

June 25, 2026

Last Modified

November 8, 2026

Advisory Details (2)

Auto-updated Nov 8, 2026
🔬 Proof of concept available. No fix on record yet.
Web page

RTKLIB 2.4.3 - Out-of-bounds Write in decode_type1033 via Crafted RTCM3 Message | Advisories | VulnCheck

https://www.vulncheck.com/advisories/rtklib-out-of-bounds-write-in-decode-type1033-via-crafted-rtcm3-message
Web page🟡 PoC Available

Out-of-Bounds Write in RTKLIB decode_type1033 via Unbounded RTCM3 Antenna/Receiver Descriptor Lengths · Issue #799 · tomojitakasu/RTKLIB · GitHub

https://github.com/tomojitakasu/RTKLIB/issues/799

Vendor Advisories for CVE-2026-56786(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
rtklib2.4.3+dfsg1-2.1 ... 2.4.3.b34+dfsg-1 (8 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
rtklib2.4.3.b34+dfsg-1
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
rtklib2.4.3.b34+dfsg-1
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
rtklib2.4.3.b34+dfsg-1
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 58× 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.

Showing the most recent 100 of 544 rows 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 444 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 23:51 UTCEchelonGraph re-scored
  2. 2026-11-12 23:51 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.7% · 54th percentile
  4. 2026-11-11 21:27 UTCEchelonGraph re-scored
  5. 2026-11-11 21:27 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  6. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  7. 2026-11-10 19:02 UTCEchelonGraph re-scored
  8. 2026-11-10 19:02 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-11-10 16:44 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  10. 2026-11-09 16:39 UTCEchelonGraph re-scored
  11. 2026-11-09 16:39 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  13. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  14. 2026-11-08 14:16 UTCEchelonGraph re-scored
  15. 2026-11-08 14:16 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  17. 2026-11-07 12:54 UTCEchelonGraph re-scored
  18. 2026-11-07 12:54 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  19. 2026-11-06 16:38 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  20. 2026-11-06 10:31 UTCEchelonGraph re-scored
  21. 2026-11-06 10:31 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  22. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  23. 2026-11-05 08:08 UTCEchelonGraph re-scored
  24. 2026-11-05 08:08 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
Show 75 more
  1. 2026-11-04 05:43 UTCEchelonGraph re-scored
  2. 2026-11-04 05:43 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  4. 2026-11-03 03:20 UTCEchelonGraph re-scored
  5. 2026-11-03 03:20 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  6. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  7. 2026-11-02 00:56 UTCEchelonGraph re-scored
  8. 2026-11-02 00:56 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  10. 2026-10-31 22:33 UTCEchelonGraph re-scored
  11. 2026-10-31 22:33 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  13. 2026-10-30 20:10 UTCEchelonGraph re-scored
  14. 2026-10-30 20:10 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  15. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  16. 2026-10-29 17:47 UTCEchelonGraph re-scored
  17. 2026-10-29 17:46 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  19. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  20. 2026-10-28 15:23 UTCEchelonGraph re-scored
  21. 2026-10-28 15:23 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  22. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  23. 2026-10-27 12:59 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-10-27 04:57 UTCEchelonGraph re-scored
  25. 2026-10-27 04:57 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  26. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  27. 2026-10-25 22:26 UTCEchelonGraph re-scored
  28. 2026-10-25 22:26 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  29. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  30. 2026-10-25 14:17 UTCEchelonGraph re-scored
  31. 2026-10-25 03:52 UTCEchelonGraph re-scored
  32. 2026-10-25 03:52 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  33. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  34. 2026-10-24 01:29 UTCEchelonGraph re-scored
  35. 2026-10-24 01:29 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  36. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  37. 2026-10-22 23:06 UTCEchelonGraph re-scored
  38. 2026-10-22 23:06 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  39. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  40. 2026-10-21 20:42 UTCEchelonGraph re-scored
  41. 2026-10-21 20:42 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  42. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  43. 2026-10-20 18:17 UTCEchelonGraph re-scored
  44. 2026-10-20 18:17 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  45. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  46. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  47. 2026-10-19 15:53 UTCEchelonGraph re-scored
  48. 2026-10-19 15:53 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  49. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  50. 2026-10-18 13:29 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  51. 2026-10-18 03:29 UTCEchelonGraph re-scored
  52. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  53. 2026-10-17 11:06 UTCEchelonGraph re-scored
  54. 2026-10-17 11:06 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  55. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  56. 2026-10-16 08:41 UTCEchelonGraph re-scored
  57. 2026-10-16 08:41 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  58. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  59. 2026-10-15 06:16 UTCEchelonGraph re-scored
  60. 2026-10-15 06:15 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  61. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  62. 2026-10-14 01:54 UTCEchelonGraph re-scored
  63. 2026-10-14 01:54 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  64. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  65. 2026-10-12 22:11 UTCEchelonGraph re-scored
  66. 2026-10-12 22:10 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  67. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  68. 2026-10-12 15:54 UTCEchelonGraph re-scored
  69. 2026-10-12 06:48 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  70. 2026-10-11 19:38 UTCEchelonGraph re-scored
  71. 2026-10-11 16:53 UTCEchelonGraph re-scored
  72. 2026-10-11 14:15 UTCEchelonGraph re-scored
  73. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  74. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  75. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 52nd percentile

Frequently asked(5)

What is CVE-2026-56786?
CVE-2026-56786 is a critical-severity vulnerability; its CVE record was published on June 25, 2026. RTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in decode_type1033 function that fails to clamp length counters to destination buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor fields. An attacker controlling an NTRIP or serial RTCM3 correction stream…
When was CVE-2026-56786 made public?
CVE-2026-56786 was made public on June 9, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on June 25, 2026. EchelonGraph's copy of the record carries a last-modified date of November 8, 2026; the record at its source may have been updated since.
Is CVE-2026-56786 actively exploited?
CVE-2026-56786 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-56786?
CVE-2026-56786 has a CVSS base score of 9.8 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-56786?
No fix for CVE-2026-56786 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's CNA (VulnCheck) lists tomojitakasu RTKLIB versions up to and including 2.4.3 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-56786 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-56786

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