CVE-2026-12803

HIGHPre-NVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 93% 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
Trending — 3 sources updated this week
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.7Exploit: None knownExposed: 0

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

In Bouncy Castle for Java before 1.85, KCCMBlockCipher MAC does not bind nonce when AAD is absent (cross-nonce AEAD forgery). This issue also affects Bouncy Castle for Java LTS before 2.73.12.

CVSS v3
8.7
EG Score
8.7(medium)
EG Risk
54(Track)
EG Risk 54/100SSVC: 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
Severity87% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

August 3, 2026

Last Modified

August 4, 2026

Advisory Details (3)

Auto-updated Aug 3, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
github_commit

commit 7d79aa76e984 (bcgit/bc-java)

Fix landed in bcgit/bc-java commit 7d79aa76e984 — awaiting tagged release

https://github.com/bcgit/bc-java/commit/7d79aa76e984da85f2a541cae8ba2ae56e1713bc
github_commit

commit 697794413ebf (bcgit/bc-java)

Fix landed in bcgit/bc-java commit 697794413ebf — awaiting tagged release

https://github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af
generic

Home · bcgit/bc-java Wiki · GitHub

https://github.com/bcgit/bc-java/wiki/CVE-2026-12803

Vendor Advisories for CVE-2026-12803(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 rangeFixed inDependents
bouncycastle1.68-2 ... 1.80-3 (12 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
bouncycastle1.72-2, 1.77-1, 1.80-1, 1.80-2, 1.80-3——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
bouncycastle1.80-3——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
bouncycastle1.80-3——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 26× in last 7d / 80× 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. 2026-08-21 08:06 UTCEG score recompute
  2. 2026-08-21 08:06 UTCGHSA enrichment
  3. 2026-08-20 22:55 UTCEPSS rescore
  4. 2026-08-20 20:38 UTCGHSA enrichment
  5. 2026-08-20 09:09 UTCGHSA enrichment
  6. 2026-08-19 21:42 UTCEG score recompute
  7. 2026-08-19 21:42 UTCGHSA enrichment
  8. 2026-08-19 17:03 UTCEPSS rescore
  9. 2026-08-19 10:14 UTCGHSA enrichment
  10. 2026-08-18 22:48 UTCGHSA enrichment
  11. 2026-08-18 11:18 UTCGHSA enrichment
  12. 2026-08-17 23:51 UTCEG score recompute
  13. 2026-08-17 23:51 UTCGHSA enrichment
  14. 2026-08-17 12:23 UTCGHSA enrichment
  15. 2026-08-17 00:55 UTCEG score recompute
  16. 2026-08-17 00:55 UTCGHSA enrichment
  17. 2026-08-16 14:56 UTCEPSS rescore
  18. 2026-08-16 13:28 UTCEG score recompute
  19. 2026-08-16 13:28 UTCGHSA enrichment
  20. 2026-08-16 02:14 UTCEPSS rescore
  21. 2026-08-16 02:01 UTCGHSA enrichment
  22. 2026-08-15 14:34 UTCGHSA enrichment
  23. 2026-08-15 03:07 UTCEG score recompute
  24. 2026-08-15 03:07 UTCGHSA enrichment
  25. 2026-08-15 01:30 UTCEPSS rescore
Show 55 more
  1. 2026-08-14 15:40 UTCGHSA enrichment
  2. 2026-08-14 04:14 UTCEG score recompute
  3. 2026-08-14 04:14 UTCGHSA enrichment
  4. 2026-08-13 22:00 UTCEPSS rescore
  5. 2026-08-13 16:47 UTCGHSA enrichment
  6. 2026-08-13 05:20 UTCGHSA enrichment
  7. 2026-08-12 17:51 UTCEG score recompute
  8. 2026-08-12 17:51 UTCGHSA enrichment
  9. 2026-08-12 13:50 UTCEPSS rescore
  10. 2026-08-12 06:25 UTCGHSA enrichment
  11. 2026-08-11 18:56 UTCEG score recompute
  12. 2026-08-11 18:56 UTCGHSA enrichment
  13. 2026-08-11 13:42 UTCEPSS rescore
  14. 2026-08-11 07:29 UTCEG score recompute
  15. 2026-08-11 07:29 UTCGHSA enrichment
  16. 2026-08-10 23:59 UTCEPSS rescore
  17. 2026-08-10 20:03 UTCGHSA enrichment
  18. 2026-08-10 08:36 UTCGHSA enrichment
  19. 2026-08-09 21:10 UTCEG score recompute
  20. 2026-08-09 21:10 UTCGHSA enrichment
  21. 2026-08-09 13:46 UTCEPSS rescore
  22. 2026-08-09 09:43 UTCGHSA enrichment
  23. 2026-08-08 22:17 UTCEG score recompute
  24. 2026-08-08 22:17 UTCGHSA enrichment
  25. 2026-08-08 16:37 UTCEPSS rescore
  26. 2026-08-08 10:50 UTCGHSA enrichment
  27. 2026-08-07 23:23 UTCEG score recompute
  28. 2026-08-07 23:23 UTCGHSA enrichment
  29. 2026-08-07 11:56 UTCGHSA enrichment
  30. 2026-08-07 00:29 UTCEG score recompute
  31. 2026-08-07 00:29 UTCGHSA enrichment
  32. 2026-08-06 13:46 UTCEPSS rescore
  33. 2026-08-06 13:03 UTCGHSA enrichment
  34. 2026-08-06 01:36 UTCEG score recompute
  35. 2026-08-06 01:36 UTCGHSA enrichment
  36. 2026-08-05 19:17 UTCEPSS rescore
  37. 2026-08-05 14:10 UTCGHSA enrichment
  38. 2026-08-05 02:20 UTCEG score recompute
  39. 2026-08-05 02:20 UTCGHSA enrichment
  40. 2026-08-04 15:09 UTCEPSS rescore
  41. 2026-08-04 14:54 UTCEG score recompute
  42. 2026-08-04 14:54 UTCGHSA enrichment
  43. 2026-08-04 10:38 UTCEPSS rescore
  44. 2026-08-04 04:03 UTCGHSA enrichment
  45. 2026-08-03 16:36 UTCEG score recompute
  46. 2026-08-03 16:36 UTCGHSA enrichment
  47. 2026-08-03 15:28 UTCEG score recompute
  48. 2026-08-03 15:28 UTCGHSA enrichment
  49. 2026-08-03 07:29 UTCEG score recompute
  50. 2026-08-03 07:29 UTCGHSA enrichment
  51. 2026-08-03 06:39 UTCEG score recompute
  52. 2026-08-03 06:39 UTCGHSA enrichment
  53. 2026-08-03 04:18 UTCEG score recompute
  54. 2026-08-03 04:04 UTCEG score recompute
  55. 2026-08-03 04:03 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-12803?
CVE-2026-12803 is a high vulnerability published on August 3, 2026. In Bouncy Castle for Java before 1.85, KCCMBlockCipher MAC does not bind nonce when AAD is absent (cross-nonce AEAD forgery). This issue also affects Bouncy Castle for Java LTS before 2.73.12.
When was CVE-2026-12803 disclosed?
CVE-2026-12803 was first published in the National Vulnerability Database on August 3, 2026, with the most recent update on August 4, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-12803 actively exploited?
CVE-2026-12803 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 92.8% of all scored CVEs.
What is the CVSS score of CVE-2026-12803?
CVE-2026-12803 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-12803?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-12803, 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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-12803

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