CVE-2026-56740

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

“—” 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: 0.9% (59th 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-2026-45343 (ENISA EUVD) · GHSA-47qp-hqvx-6r3f (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines 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: 0.9%CVSS: 7.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

JLine is a Java library for handling console input. Prior to 3.30.14, 4.0.16, and 4.2.1, the JLine3 Telnet server remote-telnet module does not limit the number of environment variables a client may inject via the Telnet NEW-ENVIRON option, and TelnetIO.readNEVariables() in TelnetIO.java:1127-1180 stores each variable pair in a HashMap held by ConnectionData, allowing an unauthenticated attacker to flood unique variable pairs before the terminating IAC SE byte and exhaust JVM heap memory with an OutOfMemoryError. This issue is fixed in versions 3.30.14, 4.0.16, and 4.2.1.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100

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.
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 or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (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
0.9%
EPSS %ILE
59th
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
0.9% 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: 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 public PoC (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.

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

July 17, 2026

Last Modified

October 24, 2026

Advisory Details (9)

Auto-updated Jul 17, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

JLine 3.30.14

Patch available: jline/jline3 jline-3.30.14

https://github.com/jline/jline3/releases/tag/jline-3.30.14
GitHub release Patch Available

JLine 4.2.1

Patch available: jline/jline3 4.2.1

https://github.com/jline/jline3/releases/tag/4.2.1
GitHub release Patch Available

JLine 4.0.16

Patch available: jline/jline3 4.0.16

https://github.com/jline/jline3/releases/tag/4.0.16
GitHub commit Patch Available

commit 934f09e6128c (jline/jline3)

Patch available: jline/jline3 4.2.1 (contains commit 934f09e6128c)

https://github.com/jline/jline3/commit/934f09e6128cee33c2b13d42b6e859c1ee2d194b
GitHub commit Patch Available

commit 4ee3a73849ff (jline/jline3)

Patch available: jline/jline3 jline-3.30.14 (contains commit 4ee3a73849ff)

https://github.com/jline/jline3/commit/4ee3a73849ffb9a85ec748e4e8cd8f6d81f84f40
GitHub commit Patch Available

commit 0389f0ee6d03 (jline/jline3)

Patch available: jline/jline3 4.0.16 (contains commit 0389f0ee6d03)

https://github.com/jline/jline3/commit/0389f0ee6d0375901b602671ad5dafd4d1d4ee09
GitHub pull request Patch Available

fix: backport telnet DoS mitigations (GHSA-47qp, GHSA-2r2c) to 4.0.x

Patch available: jline/jline3 4.0.16 (PR #2001 merged 2026-06-26)

https://github.com/jline/jline3/pull/2001
GitHub pull request Patch Available

fix: backport telnet DoS mitigations (GHSA-47qp, GHSA-2r2c) to 3.x

Patch available: jline/jline3 jline-3.30.14 (PR #2000 merged 2026-06-26)

https://github.com/jline/jline3/pull/2000
GitHub advisoryMentions a patch (unverified)

Unauthenticated Remote Memory Exhaustion via Unbounded Telnet NEW-ENVIRON Variables · Advisory · jline/jline3 · GitHub

https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f

Vendor Advisories for CVE-2026-56740(1)

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

Affected Packages

(13 across 5 ecosystems)
Debian:11(3)
PackageVulnerable rangeFix by version rangeDependents
jline1.0-3
  • every version on: no fix on record
—
jline22.14.6-4, 2.14.6-5, 2.14.6-6
  • every version on: no fix on record
—
jline33.3.1-2, 3.3.1-3, 3.3.1-4, 3.3.1-5
  • every version on: no fix on record
—
Debian:12(3)
PackageVulnerable rangeFix by version rangeDependents
jline1.0-3
  • every version on: no fix on record
—
jline22.14.6-5, 2.14.6-6
  • every version on: no fix on record
—
jline33.3.1-3, 3.3.1-4, 3.3.1-5
  • every version on: no fix on record
—
Debian:13(3)
PackageVulnerable rangeFix by version rangeDependents
jline1.0-3
  • every version on: no fix on record
—
jline22.14.6-6
  • every version on: no fix on record
—
jline33.3.1-4, 3.3.1-5
  • every version on: no fix on record
—
Debian:14(3)
PackageVulnerable rangeFix by version rangeDependents
jline1.0-3
  • every version on: no fix on record
—
jline22.14.6-6
  • every version on: no fix on record
—
jline33.3.1-4, 3.3.1-5
  • every version on: no fix on record
—
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
org.jline:jline-remote-telnet3.10.0 ... 3.9.0 (62 versions)
  • 4.1.0 up to 4.2.1: fixed in 4.2.1
  • 4.0.0 up to 4.0.16: fixed in 4.0.16
  • every version up to 3.30.14: fixed in 3.30.14
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 41× 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 153 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 53 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  2. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  3. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  4. 2026-10-25 14:18 UTCEG score recompute
  5. 2026-10-24 20:27 UTCEG score recompute
  6. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  7. 2026-10-23 18:30 UTCEG score recompute
  8. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  9. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  10. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  11. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  12. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  13. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  14. 2026-10-18 03:29 UTCEG score recompute
  15. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  16. 2026-10-17 02:54 UTCEG score recompute
  17. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  18. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  19. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  20. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  21. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  22. 2026-10-12 15:54 UTCEG score recompute
  23. 2026-10-11 19:38 UTCEG score recompute
  24. 2026-10-11 16:53 UTCEG score recompute
  25. 2026-10-11 14:16 UTCEG score recompute
Show 75 more
  1. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  2. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  3. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  4. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  5. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  6. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  7. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  8. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  9. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  10. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  11. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  12. 2026-10-01 10:26 UTCEG score recompute
  13. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  14. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  15. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  16. 2026-09-28 07:50 UTCEG score recompute
  17. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  18. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  19. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  20. 2026-09-24 04:28 UTCEG score recompute
  21. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  22. 2026-09-23 02:24 UTCEG score recompute
  23. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  24. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-09-18 04:31 UTCEG score recompute
  26. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  27. 2026-09-17 10:14 UTCEG score recompute
  28. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  29. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  30. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  31. 2026-09-14 03:18 UTCEG score recompute
  32. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  33. 2026-09-13 04:54 UTCEG score recompute
  34. 2026-09-11 21:05 UTCEG score recompute
  35. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  36. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  37. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  38. 2026-09-07 23:59 UTCEG score recompute
  39. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  40. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  41. 2026-09-05 20:25 UTCEG score recompute
  42. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  44. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  45. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  46. 2026-08-31 02:42 UTCEG score recompute
  47. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  48. 2026-08-30 03:14 UTCEG score recompute
  49. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  50. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  51. 2026-08-27 23:00 UTCEG score recompute
  52. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  53. 2026-08-26 22:51 UTCEG score recompute
  54. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  55. 2026-08-25 23:47 UTCEG score recompute
  56. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  57. 2026-08-24 14:54 UTCEG score recompute
  58. 2026-08-23 06:10 UTCEG score recompute
  59. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  60. 2026-08-22 08:20 UTCEG score recompute
  61. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  62. 2026-08-20 23:35 UTCEG score recompute
  63. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  64. 2026-08-20 01:45 UTCEG score recompute
  65. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  66. 2026-08-18 15:39 UTCEG score recompute
  67. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  68. 2026-08-17 14:31 UTCEG score recompute
  69. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  70. 2026-08-16 16:42 UTCEG score recompute
  71. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  72. 2026-08-16 05:48 UTCEG score recompute
  73. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  74. 2026-08-15 07:59 UTCEG score recompute
  75. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.5% · 40th percentile

Frequently asked(5)

What is CVE-2026-56740?
CVE-2026-56740 is a high-severity vulnerability; its CVE record was published on July 17, 2026. JLine is a Java library for handling console input. Prior to 3.30.14, 4.0.16, and 4.2.1, the JLine3 Telnet server remote-telnet module does not limit the number of environment variables a client may inject via the Telnet NEW-ENVIRON option, and TelnetIO.readNEVariables() in TelnetIO.java:1127-1180…
When was the CVE record for CVE-2026-56740 published?
The CVE record for CVE-2026-56740 was published on July 17, 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 October 24, 2026; the record at its source may have been updated since.
Is CVE-2026-56740 actively exploited?
CVE-2026-56740 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.9% probability of exploitation in the next 30 days (59th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-56740?
CVE-2026-56740 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-56740?
A fix for CVE-2026-56740 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-56740 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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