CVE-2026-64857

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (40th 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-2026-74954 (ENISA EUVD)Source: ENISA EUVD

5.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

tirreno, a security framework, has a session fixation issue in versions prior to 0.10.0. During authentication, tirreno validates the user's credentials and establishes the authenticated session, but it does not call session_regenerate_id() afterward. As a result, the session identifier is not rotated on login, it stays the same before and after authentication. An attacker able to fix a known session identifier in a victim's browser (for example through a network man-in-the-middle position, or a separate cross-site scripting or subdomain cookie-injection issue) could then gain access to the victim's authenticated session. The issue is fixed in v0.10.0. The session identifier is now regenerated on successful authentication, and the previous session is destroyed. There is no configuration-level workaround.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100

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)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
0.5%
EPSS %ILE
40th
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 (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-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
0.5% 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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 every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

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

September 9, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated Sep 9, 2026
Patch available. Sources: github, github_release.
GitHub release Patch Available

v0.10.0

Patch available: tirrenotechnologies/tirreno v0.10.0

https://github.com/tirrenotechnologies/tirreno/releases/tag/v0.10.0
GitHub advisoryMentions a patch (unverified)

CWE-384: Session Fixation in Login Authentication · Advisory · tirrenotechnologies/tirreno · GitHub

Affected: v0.10.0. The session identifier is now regenerated on successful

https://github.com/tirrenotechnologies/tirreno/security/advisories/GHSA-gwcm-4p9m-9mvr

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 44× 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.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  3. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  4. 2026-10-30 08:25 UTCOSV refresh
  5. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  6. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  7. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  8. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  9. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  10. 2026-10-25 14:12 UTCEG score recompute
  11. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  12. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  13. 2026-10-22 19:42 UTCEG score recompute
  14. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  15. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  16. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  17. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  18. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  19. 2026-10-18 03:22 UTCEG score recompute
  20. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  21. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  22. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  23. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  24. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  25. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 38th percentile
Show 56 more
  1. 2026-10-12 15:47 UTCEG score recompute
  2. 2026-10-11 19:32 UTCEG score recompute
  3. 2026-10-11 16:47 UTCEG score recompute
  4. 2026-10-11 14:08 UTCEG score recompute
  5. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  6. 2026-10-11 07:18 UTCEG score recompute
  7. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  8. 2026-10-10 01:02 UTCEG score recompute
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  10. 2026-10-08 23:59 UTCEG score recompute
  11. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  13. 2026-10-07 11:23 UTCEG score recompute
  14. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  15. 2026-10-06 10:19 UTCEG score recompute
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  17. 2026-10-05 09:01 UTCEG score recompute
  18. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  19. 2026-10-04 07:59 UTCEG score recompute
  20. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  21. 2026-10-03 06:52 UTCEG score recompute
  22. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  23. 2026-10-02 05:49 UTCEG score recompute
  24. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  25. 2026-10-01 03:05 UTCEG score recompute
  26. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  27. 2026-09-30 02:02 UTCEG score recompute
  28. 2026-09-28 17:12 UTCEG score recompute
  29. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  30. 2026-09-27 16:06 UTCEG score recompute
  31. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  32. 2026-09-26 15:03 UTCEG score recompute
  33. 2026-09-25 13:14 UTCEG score recompute
  34. 2026-09-24 12:12 UTCEG score recompute
  35. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  36. 2026-09-23 11:09 UTCEG score recompute
  37. 2026-09-22 10:07 UTCEG score recompute
  38. 2026-09-21 09:04 UTCEG score recompute
  39. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  40. 2026-09-20 08:02 UTCEG score recompute
  41. 2026-09-19 06:31 UTCEG score recompute
  42. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  43. 2026-09-18 05:29 UTCEG score recompute
  44. 2026-09-17 04:26 UTCEG score recompute
  45. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  46. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  47. 2026-09-16 03:23 UTCEG score recompute
  48. 2026-09-14 01:16 UTCEG score recompute
  49. 2026-09-13 00:14 UTCEG score recompute
  50. 2026-09-11 23:12 UTCEG score recompute
  51. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  52. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  53. 2026-09-09 15:28 UTCEG score recompute
  54. 2026-09-09 14:20 UTCEG score recompute
  55. 2026-09-09 13:45 UTCEG score recomputeFirst assessed: 5.3 MEDIUM
  56. 2026-09-09 13:44 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-64857?
CVE-2026-64857 is a medium-severity vulnerability; its CVE record was published on September 9, 2026. tirreno, a security framework, has a session fixation issue in versions prior to 0.10.0. During authentication, tirreno validates the user's credentials and establishes the authenticated session, but it does not call session_regenerate_id() afterward. As a result, the session identifier is not…
When was the CVE record for CVE-2026-64857 published?
The CVE record for CVE-2026-64857 was published on September 9, 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 September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-64857 actively exploited?
CVE-2026-64857 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-64857?
CVE-2026-64857 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-64857?
A fix for CVE-2026-64857 is available: update to the fixed version the vendor names in its advisory.

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