CVE-2026-71890

HIGHPre-NVD 8.78.7
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (16th 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-2026-92006 (ENISA EUVD) · GHSA-jc55-7frr-fv5r (GitHub Security Advisories)Source: ENISA EUVD

8.7EG
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).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 8.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In Bouncy Castle for Java before 1.86, validation of an MLS (RFC 9420) external commit's proposal list, org.bouncycastle.mls.protocol.Group.validateExternalCachedProposals, counted the proposals by type and bounded the removed leaf index but never established that the removed leaf had anything to do with the joiner. RFC 9420 sec. 12.2 permits at most one Remove proposal in an external commit, with which the joiner removes an old version of themselves, and requires that where one is present the LeafNode in the commit's path field meet the criteria it would have to meet in an Update for the removed leaf, in particular that its credential present identifiers acceptable for the removed participant. The ordinary proposal-list validator's self-remove rule is deliberately not applied on this path, because a resync commit legitimately removes a leaf the joiner owns, but nothing was put in its place. Any party holding the group's public GroupInfo, which is precisely what an external joiner is meant to be given, could therefore commit a Remove naming any member's LeafIndex and have every member apply it, evicting that member and taking over their slot in the ratchet tree. The credential check that should have prevented this existed only in the gRPC interop harness and so protected no other caller of the public Group.externalJoin and Group.handle API. An external commit carrying a Remove is now accepted only when the removed leaf's credential is identical to the one in the joiner's own new leaf, on both the sending and the receiving side.

CVSS
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
54
EG Risk 54/100

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)
Severity87% × 45%
Impact severity (EG Severity): CVSS 8.7 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 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
0.2%
EPSS %ILE
16th
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 (8.7): severity, escalated by confirmed exploitation. This CVE's 8.7 is its impact severity (EG Severity), not escalated.

EG Severity
8.7 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-10). 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

October 3, 2026

Last Modified

October 6, 2026

Advisory Details (2)

Auto-updated Oct 3, 2026
Patch available. Sources: github_commit.
GitHub commit

commit 7e8bb10eb90b (bcgit/bc-java)

Fix landed in bcgit/bc-java commit 7e8bb10eb90b — awaiting tagged release

https://github.com/bcgit/bc-java/commit/7e8bb10eb90baddf3f10b8679f627462b9522d24
Web page

CVE‐2026‐71890 · bcgit/bc-java Wiki · GitHub

https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9071890

Vendor Advisories for CVE-2026-71890(1)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
bouncycastle1.72-2 ... 1.86-1 (6 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
bouncycastle1.80-3, 1.86-1
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
bouncycastle1.80-3
  • every version up to 1.86-1: fixed in 1.86-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 36× 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 → 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.

  1. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  2. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  3. 2026-11-11 03:56 UTCEchelonGraph re-scored
  4. 2026-11-11 03:56 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  5. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  6. 2026-11-10 12:54 UTCEchelonGraph re-scored
  7. 2026-11-10 12:54 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  8. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  9. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  10. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  11. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  12. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  13. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  14. 2026-11-03 20:19 UTCEchelonGraph re-scored
  15. 2026-11-03 20:19 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  16. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  17. 2026-11-03 15:24 UTCEchelonGraph re-scored
  18. 2026-11-03 15:24 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  19. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  20. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  21. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  22. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  23. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  24. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  25. 2026-10-27 21:08 UTCEchelonGraph re-scored
Show 69 more
  1. 2026-10-27 21:08 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  2. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  3. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  4. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.2% · 16th percentile
  5. 2026-10-25 14:07 UTCEchelonGraph re-scored
  6. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  7. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  8. 2026-10-22 11:53 UTCEchelonGraph re-scored
  9. 2026-10-22 11:53 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  10. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  11. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  12. 2026-10-20 08:44 UTCEchelonGraph re-scored
  13. 2026-10-20 08:44 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  14. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  15. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  16. 2026-10-18 03:16 UTCEchelonGraph re-scored
  17. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  18. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  19. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  20. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  21. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  22. 2026-10-13 08:24 UTCEchelonGraph re-scored
  23. 2026-10-13 08:24 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  24. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  25. 2026-10-12 15:42 UTCEchelonGraph re-scored
  26. 2026-10-11 19:28 UTCEchelonGraph re-scored
  27. 2026-10-11 18:49 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  28. 2026-10-11 16:43 UTCEchelonGraph re-scored
  29. 2026-10-11 14:03 UTCEchelonGraph re-scored
  30. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  31. 2026-10-11 07:33 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  32. 2026-10-10 20:17 UTCEchelonGraph re-scored
  33. 2026-10-10 20:17 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  34. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  35. 2026-10-10 09:00 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  36. 2026-10-09 21:44 UTCEchelonGraph re-scored
  37. 2026-10-09 21:44 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  38. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  39. 2026-10-09 10:27 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  40. 2026-10-08 23:10 UTCEchelonGraph re-scored
  41. 2026-10-08 23:10 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  42. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  43. 2026-10-08 11:54 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  44. 2026-10-08 00:38 UTCEchelonGraph re-scored
  45. 2026-10-08 00:38 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  46. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  47. 2026-10-07 13:23 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  48. 2026-10-07 02:07 UTCEchelonGraph re-scored
  49. 2026-10-07 02:07 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  50. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  51. 2026-10-06 14:51 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  52. 2026-10-06 03:43 UTCEchelonGraph re-scored
  53. 2026-10-06 03:43 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  54. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  55. 2026-10-05 16:28 UTCEchelonGraph re-scored
  56. 2026-10-05 16:28 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  57. 2026-10-05 16:11 UTCEchelonGraph re-scored
  58. 2026-10-05 16:11 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  59. 2026-10-05 06:33 UTCEchelonGraph re-scored
  60. 2026-10-05 06:33 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  61. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  62. 2026-10-04 19:17 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  63. 2026-10-04 08:01 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  64. 2026-10-03 20:43 UTCEchelonGraph re-scored
  65. 2026-10-03 20:43 UTCGHSA enrichmentGHSA-jc55-7frr-fv5r · GitHub severity HIGH
  66. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  67. 2026-10-03 09:25 UTCEchelonGraph re-scored
  68. 2026-10-03 09:04 UTCEchelonGraph re-scoredFirst assessed: 8.7 HIGH
  69. 2026-10-03 09:04 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-71890?
CVE-2026-71890 is a high-severity vulnerability; its CVE record was published on October 3, 2026. In Bouncy Castle for Java before 1.86, validation of an MLS (RFC 9420) external commit's proposal list, org.bouncycastle.mls.protocol.Group.validateExternalCachedProposals, counted the proposals by type and bounded the removed leaf index but never established that the removed leaf had anything to…
When was the CVE record for CVE-2026-71890 published?
The CVE record for CVE-2026-71890 was published on October 3, 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 6, 2026; the record at its source may have been updated since.
Is CVE-2026-71890 actively exploited?
CVE-2026-71890 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (16th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-71890?
CVE-2026-71890 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-71890?
A fix for CVE-2026-71890 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-71890 are linked in the Vendor Advisories panel on this page.

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