CVE-2026-16001

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (6th percentile of EPSS-scored CVEs). 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 — 4 sources updated this week
8.2EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 8.2Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

Exposure of the message authentication key through the encryption keystream in the stream mode of IesEngine (an IesEngine constructed without a block cipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has observed one encrypted message with known plaintext to forge shorter messages of their choosing that the recipient accepts as authentic, via a crafted ciphertext and MAC tag, because the MAC key was taken from the key derivation output directly after a keystream as long as the message, while the derivation input depends only on the static key pair and fixed parameters. The keystream revealed by that one message therefore contains the MAC key for every sufficiently shorter message.

CVSS v3
8.2
EG Score
8.2HIGHmedium confidence
EG Risk
37
EG Risk 37/100CISA SSVC

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
Severity82% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.
EPSS PROB
0.2%
EPSS %ILE
6th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

October 2, 2026

Last Modified

October 2, 2026

Advisory Details (2)

Auto-updated Oct 2, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
github_commit

commit f881400b7611 (bcgit/bc-csharp)

Fix landed in bcgit/bc-csharp commit f881400b7611 — awaiting tagged release

https://github.com/bcgit/bc-csharp/commit/f881400b761134160ec2a05fd27c3e569453788d
generic

CVE 2026 16001 · bcgit/bc-csharp Wiki · GitHub

https://github.com/bcgit/bc-csharp/wiki/CVE-2026-16001

Vendor Advisories for CVE-2026-16001(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 15× 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. 2026-10-04 07:55 UTCGHSA enrichment
  2. 2026-10-03 19:23 UTCEG score recompute
  3. 2026-10-03 19:23 UTCGHSA enrichment
  4. 2026-10-03 14:25 UTCEPSS rescore
  5. 2026-10-03 06:52 UTCGHSA enrichment
  6. 2026-10-02 18:20 UTCGHSA enrichment
  7. 2026-10-02 18:20 UTCEG score recompute
  8. 2026-10-02 18:20 UTCGHSA enrichment
  9. 2026-10-02 18:20 UTCGHSA enrichment
  10. 2026-10-02 18:00 UTCEG score recompute
  11. 2026-10-02 18:00 UTCGHSA enrichment
  12. 2026-10-02 14:45 UTCGHSA enrichment
  13. 2026-10-02 07:25 UTCEG score recompute
  14. 2026-10-02 07:06 UTCEG score recompute
  15. 2026-10-02 07:05 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-16001?
CVE-2026-16001 is a high vulnerability published on October 2, 2026. Exposure of the message authentication key through the encryption keystream in the stream mode of IesEngine (an IesEngine constructed without a block cipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has observed one encrypted message with known…
When was CVE-2026-16001 disclosed?
CVE-2026-16001 was first published on October 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-16001 actively exploited?
CVE-2026-16001 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (6th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-16001?
CVE-2026-16001 has a CVSS base score of 8.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-16001?
An upstream fix for CVE-2026-16001 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-16001 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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