CVE-2026-33697

MEDIUMNVD 6.36.3
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.3 under NVD CVSS v3. EPSS exploit probability: <0.1% (below the 1st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Elevated

Also known asEUVD-2026-16488 (ENISA EUVD)Source: ENISA EUVD

6.3EG
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 (the SSVC decision on this page).
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: <0.1%CVSS: 6.3Exploit: Public PoCExposed 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 description, written by its CNA (GitHub, Inc.), states the affected versions: "The current implementation of attested TLS (aTLS) in CoCoS is vulnerable to a relay attack affecting all versions from v0.4.0 through v0.8.2." No release containing a fix is confirmed on record.

Cocos AI is a confidential computing system for AI. The current implementation of attested TLS (aTLS) in CoCoS is vulnerable to a relay attack affecting all versions from v0.4.0 through v0.8.2. This vulnerability is present in both the AMD SEV-SNP and Intel TDX deployment targets supported by CoCoS. In the affected design, an attacker may be able to extract the ephemeral TLS private key used during the intra-handshake attestation. Because the attestation evidence is bound to the ephemeral key but not to the TLS channel, possession of that key is sufficient to relay or divert the attested TLS session. A client will accept the connection under false assumptions about the endpoint it is communicating with — the attestation report cannot distinguish the genuine attested service from the attacker's relay. This undermines the intended authentication guarantees of attested TLS. A successful attack may allow an attacker to impersonate an attested CoCoS service and access data or operations that the client intended to send only to the genuine attested endpoint. Exploitation requires the attacker to first extract the ephemeral TLS private key, which is possible through physical access to the server hardware, transient execution attacks, or side-channel attacks. Note that the aTLS implementation was fully redesigned in v0.7.0, but the redesign does not address this vulnerability. The relay attack weakness is architectural and affects all releases in the v0.4.0–v0.8.2 range. This vulnerability class was formally analyzed and demonstrated across multiple attested TLS implementations, including CoCoS, by researchers whose findings were disclosed to the IETF TLS Working Group. Formal verification was conducted using ProVerif. As of time of publication, there is no patch available. No complete workaround is available. The following hardening measures reduce but do not eliminate the risk: Keep TEE firmware and microcode up to date to reduce the key-extraction surface; define strict attestation policies that validate all available report fields, including firmware versions, TCB levels, and platform configuration registers; and/or enable mutual aTLS with CA-signed certificates where deployment architecture permits.

CVSS v3
6.3
EG Score
6.3MEDIUMmedium confidence
EG Risk
44
EG Risk 44/100

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)
Severity63% × 45%
Impact severity (EG Severity): CVSS 6.3 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.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
<0.1%
EPSS %ILE
below the 1st
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 (6.3): severity, escalated by confirmed exploitation. This CVE's 6.3 is its impact severity (EG Severity), not escalated.

EG Severity
6.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
<0.1% within 30 daysSource: FIRST EPSS. 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; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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; Track* at high (mission-essential systems).

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.

Exploitation none (CISA Vulnrichment) · Automatable no (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)14 days if the affected system is publicly exposed; Fix on system upgrade 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. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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

March 27, 2026

Last Modified

June 17, 2026

Advisory Details (1)

Auto-updated Aug 6, 2026
No fix on record yet. Sources: github.
GitHub advisoryMentions a patch (unverified)

CoCoS attested TLS is vulnerable to relay attacks via extracted ephemeral TLS keys · Advisory · ultravioletrs/cocos · GitHub

https://github.com/ultravioletrs/cocos/security/advisories/GHSA-vfgg-mvxx-mgg7

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 24× 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 88 of 99 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. 12 repeat rows among the latest 100 are merged into the row they repeat. The 11 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-31 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  2. 2026-10-30 20:55 UTCOSV refresh
  3. 2026-10-30 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  4. 2026-10-29 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  5. 2026-10-27 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  6. 2026-10-25 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  7. 2026-10-25 14:34 UTCEG score recompute
  8. 2026-10-23 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  9. 2026-10-23 03:29 UTCEG score recompute
  10. 2026-10-22 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  11. 2026-10-19 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  12. 2026-10-18 03:46 UTCEG score recompute
  13. 2026-10-17 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  14. 2026-10-16 16:41 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  15. 2026-10-12 16:13 UTCEG score recompute
  16. 2026-10-11 19:55 UTCEG score recompute
  17. 2026-10-11 17:08 UTCEG score recompute
  18. 2026-10-11 14:35 UTCEG score recompute
  19. 2026-10-11 04:01 UTCOSV refresh
  20. 2026-10-10 20:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  21. 2026-10-08 17:12 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  22. 2026-10-07 23:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  23. 2026-10-06 15:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  24. 2026-10-04 23:22 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  25. 2026-09-21 16:19 UTCOSV refresh
Show 63 more
  1. 2026-09-17 19:30 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  2. 2026-09-16 14:08 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  3. 2026-09-16 05:15 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  4. 2026-09-13 16:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  5. 2026-09-12 15:01 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  6. 2026-09-11 14:53 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  7. 2026-09-11 09:37 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  8. 2026-09-10 09:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  9. 2026-09-08 22:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  10. 2026-09-06 13:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  11. 2026-09-04 05:06 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  12. 2026-09-02 14:11 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  13. 2026-09-02 13:14 UTCOSV refresh
  14. 2026-09-01 13:53 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  15. 2026-08-30 19:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  16. 2026-08-28 21:41 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  17. 2026-08-27 14:25 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  18. 2026-08-26 14:46 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  19. 2026-08-25 13:49 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  20. 2026-08-24 14:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  21. 2026-08-23 00:19 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  22. 2026-08-19 17:03 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  23. 2026-08-18 13:48 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  24. 2026-08-17 13:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  25. 2026-08-16 10:03 UTCEG score recompute
  26. 2026-08-16 02:14 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  27. 2026-08-12 22:33 UTCEG score recompute
  28. 2026-08-12 13:50 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  29. 2026-08-10 07:42 UTCEG score recompute
  30. 2026-08-09 13:46 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  31. 2026-08-09 05:55 UTCEG score recompute
  32. 2026-08-08 16:37 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  33. 2026-08-07 16:21 UTCEG score recompute
  34. 2026-08-06 13:46 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  35. 2026-08-06 00:49 UTCEG score recompute
  36. 2026-08-05 19:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  37. 2026-08-04 15:10 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  38. 2026-08-02 15:14 UTCEG score recompute▼ 1.20
  39. 2026-08-02 02:27 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  40. 2026-08-01 04:16 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  41. 2026-07-30 16:28 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  42. 2026-07-26 14:54 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  43. 2026-07-25 14:18 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  44. 2026-07-24 14:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  45. 2026-07-23 03:09 UTCEG score recompute
  46. 2026-07-17 04:54 UTCOSV refresh
  47. 2026-07-08 15:15 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  48. 2026-07-07 13:46 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  49. 2026-07-06 16:27 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  50. 2026-06-29 03:32 UTCOSV refresh
  51. 2026-06-28 04:56 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  52. 2026-06-17 17:53 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  53. 2026-06-15 17:49 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  54. 2026-06-12 23:12 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  55. 2026-06-11 14:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  56. 2026-06-10 13:22 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  57. 2026-06-05 22:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  58. 2026-06-04 13:12 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  59. 2026-06-02 20:13 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  60. 2026-06-01 13:51 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  61. 2026-06-01 06:13 UTCOSV refresh
  62. 2026-05-31 00:16 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  63. 2026-05-29 13:44 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile

Publicly available exploits

(1 reference)

Public exploit code is referenced for this CVE (1 GitHub PoC). No fix is confirmed yet, so defenders should restrict or isolate affected systems accordingly until one is published.

  • GitHub PoCmuhammad-usama-sardar/intra-handshake-fail
    Published Jul 6, 2026

    Early Attestation Considered Harmful (CVE-2026-33697)

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-33697?
CVE-2026-33697 is a medium-severity vulnerability; its CVE record was published on March 27, 2026. Cocos AI is a confidential computing system for AI. The current implementation of attested TLS (aTLS) in CoCoS is vulnerable to a relay attack affecting all versions from v0.4.0 through v0.8.2. This vulnerability is present in both the AMD SEV-SNP and Intel TDX deployment targets supported by…
When was the CVE record for CVE-2026-33697 published?
The CVE record for CVE-2026-33697 was published on March 27, 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 June 17, 2026; the record at its source may have been updated since.
Is CVE-2026-33697 actively exploited?
CVE-2026-33697 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a <0.1% probability of exploitation in the next 30 days (below the 1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33697?
CVE-2026-33697 has a CVSS v3 base score of 6.3 (NVD).
How do I remediate CVE-2026-33697?
No fix for CVE-2026-33697 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 description, written by its CNA (GitHub, Inc.), states the affected versions: "The current implementation of attested TLS (aTLS) in CoCoS is vulnerable to a relay attack affecting all versions from v0.4.0 through v0.8.2." No release containing a fix is confirmed on record.

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